Chapter 7

shorter winter sleep than any of its companions, it usually makes its appearance on the wing by the middle of March, and continues active until quite late in the year; in fact Mr. Gould has recorded the fact of his having shot a specimen of it on a warm sunny day just before Christmas. For the purpose of hibernation the Bats retire to their usual resting-places, but frequently, instead of suspending themselves by their hind feet, as when sleeping, pack themselves away in small parties in holes and crevices, an arrangement which probably furnishes a better protection against the inclemency of the season.

It is probably in the dormitory that the birth of the young bats takes place--at least, so far as we know, the process is affected in a manner which must preclude active exertions on the part of the mother for some little time. The best account of the operation with which we are acquainted is that given fifty years ago by Mr. George Daniell, in a paper read before the Zooelogical Society, in which he described the habits of some Noctules kept by him in captivity. Four out of five died, and the survivor, a female, was observed on 23d June to become very restless, and to continue so for about an hour, although still suspended by the hind limbs in the attitude of repose. "Suddenly," to use Mr. Daniell's words, "she reversed her position, and attached herself by her anterior limbs to a cross wire of the cage, stretching her hind limbs to their utmost extent, curving the tail upwards, and expanding the interfemoral membrane, so as to form a perfect nestlike cavity for the reception of the young ... which was born on its back, perfectly destitute of hair, and blind. The mother then cleaned it, turning it over in its nest; and afterwards, resuming her usual position, placed the young in the membrane of her wing. She next cleaned herself, and wrapped up the young one so closely as to prevent any observation of the process of suckling. At the time of birth the young was larger than a new-born mouse, and its hind legs and claws were remarkably strong and serviceable, enabling it not only to cling to its dam, but also to the deal sides of the cage. On the 24th the animal took her food in the morning, and appeared very careful of her young, shifting it from side to side to suckle it, and folding it in the membranes of the tail and wings." Unfortunately, these interesting observations were cut short by the death of the mother, and the young animal, which was with some difficulty removed from the nipple, survived only eight days, during which it was fed with milk from a sponge, and made but little progress, its eyes being still unopened, and its body almost hairless.

There can be no doubt that this process, varied in minor points in accordance with differences of structure, reveals to us what takes place in Bats generally in immediate connection with the birth of the young. From all the observations that have been made it appears certain that the female Bats produce only a single young one at a birth; that this is at first blind, naked, and helpless; and that the female nurses it carefully--a process which must be greatly facilitated by the power of clinging to its parent possessed by the young Bat from the first moment of its appearance in the world. The two nipples possessed by the female are situated upon the breast, sometimes quite at the sides under the arm-pits, a position which renders it particularly easy for the careful mother to tend her offspring, while she is also enabled to carry it about with her in her evening flights, the young creature clinging firmly to its mother's fur, and being quite out of the way of the movements of the wings. This part of the business, of course, could not be exemplified in Mr. Daniell's case, as the female was imprisoned in a cage, but it is a well-known fact in the natural history of these creatures that the mother does carry her young about with her so long as it continues helpless. Apparently, indeed, even after the young animal becomes capable of flying about, its mother still retains some interest in its well-being--at least, if we may apply generally a case recorded by Dr. Allen in his account of the Bats of North America. It relates to a small species, the Red Bat, very common throughout the United States, a young individual of which having been captured by a lad, "three hours afterwards, in the evening, as he was conveying it to the museum in his hand, while passing near the place where it was caught, the mother made her appearance, and followed the boy for two squares, flying around him, and finally alighted on his breast, such was her anxiety to save her offspring. Both were brought to the museum, the young one firmly adhering to its mother's teat. This faithful creature lived two days in the museum, and then died of injuries received from her captor. The young one being but half grown was still too young to take care of itself, and died shortly after."

This little anecdote seems to set the moral character of the Bat in a very favorable light, at any rate as regards the family affections, and there is no doubt that the females of all the species of the group show considerable fondness for their young. In other respects, perhaps, they do not all shine quite so brilliantly, for, as we have seen, the Fruit Bats squabble very selfishly for the most convenient sleeping places, as indeed do other gregarious species of the order, and some of the former quarrel and fight over their food. As regards amiability of character, however, there is probably considerable difference between different kinds of Bats; at any rate, in confinement, they show much diversity of temper, some of them being sullen, refusing food, and biting vigorously at their captors or the bars of their prison, while others are easily tamed and soon become familiar. Two of the commonest species, the Pipistrelle, and the Long-eared Bat are among the latter. The Pipistrelle, which appears to be abundant throughout Britain, and indeed in most of the northern temperate regions of the eastern hemisphere, is a small reddish-brown species, measuring little more than one inch and a half in length without the tail, but with a spread of wing of more than eight inches. Its regular food consists chiefly of gnats, midges, and other small flies, in pursuit of which it often frequents the vicinity of water, but it has a curious predilection for raw meat, and in search of this it often makes its way into pantries, where the little thief will be found clinging to a joint of meat, and feeding upon it with avidity. This fondness for meat makes the Pipistrelle very easy to keep in confinement, as it diminishes the necessity of finding it insect food, and the little creature will in time become so tame as to take pieces of meat from its owner's fingers. It is an active and lively little creature, flying, running, and climbing about with great ease; in the latter operation, according to Professor Bell, it makes use of the extreme tip of the tail as if it was a finger.

The Long-eared Bat, so called from the great size of its ears, which are nearly as long as the whole animal exclusive of the tail, has perhaps a wider distribution than the Pipistrelle, but is hardly so abundant in Britain. Its head and body measure nearly two inches long, while its wings spread to about ten inches. This Bat generally sleeps during the day under the roofs of houses and in church towers, and when sleeping its long ears are carefully stowed away under the folded wings, but the earlet or inner lobe of the ear still projects, so that the creature appears to have a pair of short-pointed ears. The Long-eared Bat flies very late in the evening, and indeed seems to continue its activity throughout the night; its food appears to consist to a great extent of the smaller moths, although other insects are by no means disdained. This species also soon becomes very tame and familiar; it will fly about the room, play with its fellows, and come fearlessly to take its food from the hand. Professor Bell gives an interesting account of one kept by Mr. James Sowerby, which, "when at liberty in the parlor, would fly to the hand of any of the young people who held up a fly toward it, and, pitching on the hand, take the fly without hesitation. If the insect was held between the lips, the Bat would then settle on its young patron's cheek, and take the fly with great gentleness from the mouth; and so far was this familiarity carried, that, when either of the young people made a humming noise with the mouth, in imitation of an insect, the Bat would search about the lips for the promised dainty." This habit of taking its food when off the wing, would seem to be natural to the Long-eared Bat under certain circumstances, as Mr. Tomes records his having seen one feeding in this manner upon the myriads of small moths which swarmed about a spindle tree in bloom.

It is unnecessary to say that the creatures which display all this activity and intelligence are well endowed with at least all the senses possessed by the other animals of their class. The organs of smell and hearing are well developed, and in many cases associated with external membranous expansions of great size, as seen in the ears of the Long-eared Bat; and the eyes, though generally of small size except in the Fruit Bats, are bright and efficient, serving the creatures in good stead in the rapid pursuit of their insect-prey, which must be directed principally by sight. The common expression "as blind as a Bat," must be taken to apply to Bats accidentally driven from their retreats in the day-time, when it must be confessed that they fly about in a dazed manner; but at night and in their dark retreats they show no such imbecility of purpose, but find their way with astonishing precision and certainty. In fact, instead of being blind, the Bats must be especially sharp-sighted, if all their evolutions be guided by the sense of sight, for in many cases they habitually resort to the inmost recesses of caverns and other places where, so far as our judgment goes, no light can possibly penetrate. Hence it was long since suspected that some other sense than that of sight must come to their aid when they plunge into such outer darkness as prevails in some places through which they fly with the greatest freedom, and more than a century ago numerous experiment were made by a distinguished Italian naturalist, the Abbe Spallanzani, in order to discover, if possible, what might be the secret of these curious phenomena.

He set free, in a long passage which was bent at a right angle about the middle of its length, a blinded Bat, which flew through the whole of this passage, turning the corner correctly, without anywhere touching the walls; while flying, too, it in some mysterious manner detected a hole in the roof at a distance of eighteen inches, and proceeded at once to ensconce itself in this shelter. In another experiment the Abbe took two Bats, one blinded, the other not, and placed them in a space shut off from a garden and roofed in with nets, and with sixteen strings suspended from the top in different parts. Both Bats flew about briskly and avoided the hanging strings equally well, until at length the _blinded_ Bat discovered that the meshes of the net were large enough for him to get through, when he at once made his escape, and after flying about for a short time, went off directly to the only roof in the vicinity, under which he disappeared. In short, from these experiments it became perfectly clear that under these circumstances the sense of sight was not of primary importance in guiding the course of the Bat. Similar trials with the organs of smell and hearing showed that they had nothing to do with it, and the only other sense that could be appealed to was the general sense of touch. Baron Cuvier, the great French comparative anatomist, was the first to suggest, from the consideration of the results obtained by the Abbe Spallanzani and others, especially by M. de Jurine, of Geneva, that the peculiar phenomena in question might be accounted for by the existence, especially in the great membranous expansions of the wings, of a most delicate sensibility; and subsequent investigations of the structure of those organs has tended to confirm this view, so that it is now the one generally accepted. It is found that these great membranes are traversed in all parts by numerous nerves, the delicate terminations of which form little loops, exactly resembling those which occur in our skin in those parts where the sense of touch is most highly developed; and this resemblance is heightened by the fact that the membrane is covered with rows of little points. Even the organs of circulation in the wings are so constructed as to render it almost certain that those organs have a quite exceptional sensibility. Their ramifications are very numerous, and the veins as well as the arteries have contractile walls, rendering the circulation of the blood exceedingly active, the conditions, as Professor St. George Mivart remarks, being almost those of a state of inflammation.

If these membranous expansions have the functions just ascribed to them, we can easily understand that the larger they are the better, and this will explain why the Bats generally exhibit so great a tendency to run out into naked membranes. Thus although the ears, as organs of hearing, have probably nothing to do with guiding the Bat when flying in dark places, we find that in a great number of species the external ears are exceedingly large and delicately membranous, of which indeed we have an example in the British Long-eared Bat already referred to. In like manner, while the nose, as a nose, may also be left out of consideration, the development of membranous appendages of the part of the face in which the nostrils open is one of the most curious peculiarities of a vast number of Bats, in many of which these singular nose-leaves almost rival the ears in size, while their structure often renders them most grotesque. We have two Bats thus adorned in Britain, namely, the Greater and the Lesser Horseshoe Bats, but most of the leaf-nosed species are inhabitants of warmer regions, and it is there that they run out into the most remarkable eccentricities of structure. In Blainville's Bat, a small species inhabiting South America and the West Indies, these expansions of the skin of the face seem to have reached the utmost possible grotesqueness, but the membranous leaves are larger and the ears much more developed in many species allied to our own Horseshoe Bats, especially such as the Megaderms. We can hardly imagine that these great membranous expansions of the outer ears and the region of the nose can have any other purpose than that of enlarging the surface of highly sensitive skin specially adapted for the perception of external impressions, and it is a remarkable fact, strictly in accordance with this view, that, so far as we know, the Bats so endowed are more decidedly nocturnal in their habits and frequent darker retreats than their less gifted fellows. Thus our Long-eared Bat, as already stated, continues active on the wing throughout the whole night, and the Horseshoe Bats are distinguished as specially affecting dark caves.

HOW SNAKES EAT

(FROM SNAKES.)

BY CATHERINE C. HOPLEY.

The Hamadryad's appointed diet is one ring-snake per week; but "Ophi," as we now call him, is occasionally required--and with no sacrifice of his principles either--to eat an extra snake to satisfy the curiosity of some distinguished visitor. Sometimes, too, colubers are plentiful, and two small ones are not too much for his ten or twelve feet of appetite. This splendid serpent has rewarded care by remaining in perfect health, and growing several feet. He was between eight and nine feet long when he came, and is now not far short of twelve and proportionately larger in circumference. Sometimes during winter, when ring-snakes are scarce, "Ophi" is compelled to fast; for he is not then to be tempted with other food. During the first year of his residence in the Gardens, the supply was good, and he ate no less than eighty-two fellow-creatures before the winter was well over. Towards spring, however, the supply ran short, and only two more remained for him. He had now fasted two entire weeks, and looked hungry and eager. The keeper offered him a guinea-pig, at which he took great offence, raising his hood and hissing angrily for a long while. Eggs he declined, also a lizard and a rat, in great disgust. In India the Ophiophagi are said to feed on lizards and fish occasionally, but _our_ Ophiophagus preferred to fast. At last one of the two ring-snakes was produced, and Ophio was to be regaled. It was the 31st of March, 1876, and he had been a denizen of the Gardens just one year. My note-book informs me that it was a lovely, soft spring day, and that Ophio was quite lively. He had rejected frogs on his own account, but in the uncertainty of more ring-snakes arriving, he was now decoyed into eating half a dozen. Holland contrived that the snake destined for his dinner should answer the purpose of a feast, and had allowed it to eat as many frogs as it chose. Like the poor wretch who, doomed to the gallows, is permitted to fare sumptuously the last morning of his life, the ring-snake ate three frogs, by which the Ophiophagus was to derive chief benefit; he, all unconscious of the cause of his victim's unusual plumpness, swallowed him speedily.

Soon after this Ophio doffed his winter coat entire, and having again fasted for ten days, was at once rewarded by the last remaining ring-snake in a similarly plethoric condition, namely, with three more frogs inside him. Now and then during the winter months the scarcity of ring-snakes has compelled the sacrifice of some far rarer colubers to Ophio's cannibal tastes. And yet each year we hear of hundreds of ring-snakes being ruthlessly killed in country districts, while at great cost and trouble others are purchased or brought from the Continent for the Hamadryad's sustenance. Lord Lilford, one of the Ophidarium's best patrons, sometimes sends presents of game in the shape of ring-snakes to the Hamadryad.

While watching this snake-eater over his dinner, one is struck with the remarkable tenacity of life exhibited in the victim, or the slow action of the venom if poisoned in the first grasp. The Ophiophagus seizes it anywhere, that is, at whichever part happens to come first, and then, after holding it quietly for a time, works his jaws up to the head in the usual hand-over-hand, or "jaw-after-jaw" fashion, invariably swallowing the snake head first. On one occasion when I watched attentively, Ophio, having seized a ring-snake by the middle, held it doggedly still for one quarter of an hour, while the lesser snake did its very best to work its way out of the jaws, and also to fetter its captor by twirling itself over his head and coiling round his neck. This continued while Ophio, with his head and neck raised, remained motionless, and after the quarter of an hour commenced to work his jaws up towards the head of the ring snake, which, as more and more of its own body was free for action, twirled itself about, and at length coiled its tail round the bit of branch nailed into the cage.

Persistently, like a sailor making his vessel fast to the windlass, the ring snake lashed as much of himself as was free round the branch a foot off, and so pulled and pulled till he looked in danger of severing himself in two. Meanwhile Ophio, slowly but surely advancing, caused its head and neck to disappear, grasping tightly with his venomous jaws, as if he would say, "We'll see who is master." It was a close tussle, so firmly did the little coluber retain his hold on the "tree"; but as the upper part of him was gradually drawn into those unrelaxing jaws, he by degrees gave way, and by and by was gone.

Not far short of an hour was occupied in this meal, during which the victim showed no signs of being poisoned, nor were his coils round the stump relaxed in the slightest degree, till Ophio reached the tail. The ring snake is not a constrictor, yet he thus tied himself round the tree by the coils of his tail.

One more singular case of tenacity of life must be recorded. A ring-snake had been caught in the usual way, and the usual struggle ensued between captor and captive. Coluber, with its head tightly gripped in the jaws of his enemy, had still all the rest of himself at liberty and in full activity, and after wriggling a violent protest, he coiled what was left of himself so closely round the neck of his persecutor that the latter made little or no progress with his dinner for a time. He seemed to be deliberating how to proceed next, and asking, "What is the meaning of this?" then shook his head, lowered it to the shingle, and tried to rub off the coils. The only result thus achieved was that the extreme end of Coluber's tail was loosened for a moment, but only to coil afresh around Ophio's jaws, which nevertheless slowly and surely advanced.

For nearly an hour the progress was very slow; but when the ring-snake was nearly all swallowed except a few inches of tail, these became so tight a muzzle that Ophio in turn was the victim. Shaking his head and vainly endeavoring to free his jaws of this muzzle, a minute or two elapsed, during which he seemed to suffer some discomfort, when suddenly his mouth opened widely, and out crawled Natrix, apparently none the worse for this temporary entombment. He had turned round when two or three feet from daylight, and come back to see the world once more. But it so happened that Ophio closed his jaws in time over the few inches of tail which still remained between them. Nor did he once relax his grasp of this, but quickly and patiently began to work his way up to the head and recommence his meal, and this time with better success. An hour and a quarter I watched, nor was any evidence of poison seen, so as to reduce the powers of the bitten snake; for bitten it must have been in those prolonged and forcible grasps.

In these conflicts one could but observe a dogged stupidity on the part of the venomous snake, who, had he but brought coils to his aid, might have simplified matters so easily. The little Heterodons, and even the Lacertines, often assist themselves with coils in managing their prey, though not themselves constrictors; but the venomous ones have not the slightest notion of helping themselves in this way, as if confident that in time their venom would do its work.

WHAT WORMS DO

(FROM THE FORMATION OF VEGETABLE MOULD.)

BY CHARLES DARWIN.

We now come to treat of a curious and important subject,--namely, the amount of earth which is brought up by worms from beneath the surface, and is afterwards spread out more or less completely by the rain and wind. The amount can be judged of by two methods,--by the rate at which objects left on the surface are buried, and more accurately by weighing the quantity brought up within a given time. We will begin with the first method, as it was first followed.

Near Maer Hall in Staffordshire, quick-lime had been spread, about the year 1827, thickly over a field of good pasture-land, which had not since been ploughed. Some square holes were dug in this field in the beginning of October, 1837, and the sections showed a layer of turf, formed by the matted roots of the grasses, 1/2 inch in thickness, beneath which, at a depth of 21/2 inches (or 3 inches from the surface), a layer of the lime in powder or in small lumps could be distinctly seen running all round the vertical sides of the holes. The soil beneath the layer of lime was either gravelly or of a coarse sandy nature, and differed considerably in appearance from the overlying dark-coloured fine mould. Coal-cinders had been spread over a part of this same field either in the year 1833 or 1834; and when the above holes were dug, that is, after an interval of 3 or 4 years, the cinders formed a line of black spots round the holes, at a depth of 1 inch beneath the surface, parallel to and above the white layer of lime. Over another part of this field cinders had been strewed, only about half a year before, and these either still lay on the surface or were entangled among the roots of the grasses; and I here saw the commencement of the burying process, for worm-castings had been heaped on several of the smaller fragments. After an interval of 43/4 years this field was re-examined, and now the two layers of lime and cinders were found almost everywhere at a greater depth than before by nearly 1 inch, we will say by 3/4 of an inch. Therefore, mould to an average thickness of .22 of an inch had been annually brought up by the worms, and had been spread over the surface of this field.

Coal-cinders had been strewed over another field, at a date which could not be positively ascertained, so thickly that they formed (October, 1837) a layer, 1 inch in thickness at a depth of about 3 inches from the surface. The layer was so continuous that the overlying dark vegetable mould was connected with the sub-soil of red clay only by the roots of the grasses; and when these were broken, the mould and the red clay fell apart. In a third field, on which coal-cinders and burnt marl had been strewed several times at unknown dates, holes were dug in 1842; and a layer of cinders could be traced at a depth of 31/2 inches, beneath which at a depth of 91/2 inches from the surface there was a line of cinders together with burnt marl. On the sides of one hole there were two layers of cinders, at 2 and 31/2 inches beneath the surface; and below them at a depth in parts of 91/2, and in other parts of 101/2 inches there were fragments of burnt marl. In a fourth field two layers of lime, one above the other could be distinctly traced, and beneath them a layer of cinders and burnt marl at a depth of from 10 to 12 inches below the surface.

A piece of waste land was enclosed, drained, ploughed, harrowed, and thickly covered in the year 1822 with burnt marl and cinders. It was sowed with grass seeds, and now supports a tolerably good but coarse pasture. Holes were dug in this field in 1837, or 15 years after its reclamation, and we see in the accompanying diagram (Fig. 1) reduced to half of the natural scale, that the turf was 1/2 inch thick, beneath which there was a layer of vegetable mould 21/2 inches thick. This layer did not contain fragments of any kind; but beneath it there was a layer of mould, 11/2 inch in thickness, full of fragments of burnt marl, conspicuous from their red color, one of which near the bottom was an inch in length; and other fragments of coal-cinders together with a few white quartz pebbles. Beneath this layer and at a depth of 41/2 inches from the surface, the original black, peaty, sandy soil with a few quartz pebbles was encountered. Here, therefore, the fragments of burnt marl and cinders had been covered in the course of 15 years by a layer of fine vegetable mould, only 21/2 inches in thickness, excluding the turf. Six and a half years subsequently this field was re-examined, and the fragments were now found at from 4 to 5 inches beneath the surface. So that in this interval of 61/2 years, about 11/2 inch of mould had been added to the superficial layer. I am surprised that a greater quantity had not been brought up during the whole 211/2 years, for in the closely underlying black, peaty soil there were many worms. It is, however, probable that formerly, whilst the land remained poor, worms were scanty; and the mould would then have accumulated slowly. The average annual increase of thickness for the whole period is .19 of an inch.

Two other cases are worth recording. In the spring of 1835 a field, which had long existed as poor pasture, and was so swampy that it trembled slightly when stamped on, was thickly covered with red sand so that the whole surface appeared at first bright red. When holes were dug in this field after an interval of about 21/2 years, the sand formed a layer at a depth of 3/4 inch beneath the surface. In 1842 (i.e., seven years after the sand had been laid on) fresh holes were dug, and now the red sand formed a distinct layer, 2 inches beneath the surface, or 11/2 inch beneath the turf; so that on an average .21 inches of mould had been annually brought to the surface. Immediately beneath the layer of red sand the original sub-stratum of black, sandy peat extended.

A grass field, likewise not far from Maer Hall, had formerly been thickly covered with marl, and was then left for several years as pasture; it was afterwards ploughed. A friend had three trenches dug in this field 28 years after the application of the marl, and a layer of the marl fragments could be traced at a depth, carefully measured, of 12 inches in some parts, and of 14 inches in other parts. This difference in depth depended on the layer being horizontal, whilst the surface consisted of ridges and furrows from the field having been ploughed. The tenant assured me that it had never been turned up to a greater depth than from 6 to 8 inches; and as the fragments formed an unbroken horizontal layer from 12 to 14 inches beneath the surface, these must have been buried by the worms whilst the land was in pasture before it was ploughed, for otherwise they would have been indiscriminately scattered by the plough throughout the whole thickness of the soil. Four and a half years afterwards I had three holes dug in this field, in which potatoes had been lately planted, and the layer of marl fragments was now found 13 inches beneath the bottoms of the furrows, and therefore probably 15 inches beneath the general level of the field. It should, however, be observed that the thickness of the blackish, sandy soil, which had been thrown up by the worms above the marl fragments in the course of 321/2 years, would have measured less than 15 inches, if the field had always remained as pasture, for the soil would in this case have been much more compact. The fragments of marl almost rested on an undisturbed sub-stratum of white sand with quartz pebbles; and as this would be little attractive to worms, the mould would hereafter be very slowly increased by their action.

We will now give some cases of the action of worms, on land differing widely from the dry, sandy, or the swampy pasture just described. The chalk formation extends all round my house in Kent; and its surface, from having been exposed during an immense period to the dissolving action of rain-water, is extremely irregular, being abruptly festooned and penetrated by many deep, well-like cavities. During the dissolution of the chalk the insoluble matter, including a vast number of unrolled flints of all sizes, has been left on the surface and forms a bed of stiff red clay, full of flints, and generally from 6 to 14 feet in thickness. Over the red clay, wherever the land has long remained as pasture, there is a layer a few inches in thickness of dark-coloured vegetable mould.

A quantity of broken chalk was spread, on December 20, 1842, over a part of a field near my house, which had existed as pasture certainly for 30, probably for twice or thrice as many, years. The chalk was laid on the land for the sake of observing at some future period to what depth it would become buried. At the end of November, 1871, that is, after an interval of twenty-nine years, a trench was dug across this part of the field; and a line of white nodules could be traced on both sides of the trench, at a depth of 7 inches from the surface. The mould, therefore (excluding the turf), had here been thrown up at an average rate of .22 inches per year. Beneath the line of chalk nodules there was in parts hardly any fine earth free of flints, while in other parts there was a layer 21/4 inches in thickness. In this latter case the mould was altogether 91/4 inches thick; and in one such spot a nodule of chalk and a smooth flint pebble, both of which must have been left at some former time on the surface, were found at this depth. At from 11 to 12 inches beneath the surface, the undisturbed reddish clay, full of flints, extended. The appearance of the above nodules of chalk surprised me much at first, as they closely resembled water-worn pebbles, whereas the freshly-broken fragments had been angular. But on examining the nodules with a lens, they no longer appeared water-worn, for their surfaces were pitted through unequal corrosion, and minute, sharp points, formed of broken fossil shells, projected from them. It was evident that the corners of the original fragments of chalk had been wholly dissolved, from presenting a large surface to the carbonic acid dissolved in the rain-water and to that generated in soil containing vegetable matter, as well as the humus-acids. The projecting corners would also, relatively to the other parts, have been embraced by a larger number of living rootlets; and these have the power of even attacking marble, as Sachs has shown. Thus, in the course of twenty-nine years, buried angular fragments of chalk had been converted into well-rounded nodules.

Another part of this same field was mossy, and as it was thought that sifted coal-cinders would improve the pasture, a thick layer was spread over this part either in 1842 or 1843, and another layer some years afterwards. In 1871 a trench was here dug, and many cinders lay in a line at a depth of 7 inches beneath the surface, with another line at a depth of 51/2 inches parallel to the one beneath. In another part of this field, which had formerly existed as a separate one, and which it was believed had been pasture-land for more than a century, trenches were dug to see how thick the vegetable mould was. By chance the first trench was made at a spot where at some former period, certainly more than forty years before, a large hole had been filled up with coarse, red clay, flints, fragments of chalk, and gravel; and here the fine vegetable mould was only from 4 1/8 to 4 3/8 inches in thickness. In another and undisturbed place, the mould varied much in thickness, namely, from 61/2 to 81/2 inches; beneath which a few small fragments of brick were found in one place. From these several cases, it would appear, that during the last 29 years mould has been heaped on the surface at an average annual rate of from .2 to .22 of an inch. But in this district when a ploughed field is first laid down in grass, the mould accumulates at a much slower rate. The rate, also, must become very much slower after a bed of mould, several inches in thickness, has been formed; for the worms then live chiefly near the surface, and burrow down to a greater depth so as to bring up fresh earth from below, only during the winter, when the weather is very cold (at which time worms were found in this field at a depth of 26 inches), and during summer, when the weather is very dry.

A field which adjoins the one just described, slopes in one part rather steeply (viz., at from 10 deg. to 15 deg.); this part was last ploughed in 1841, was then harrowed and left to become pasture-land. For several years it was clothed with an extremely scant vegetation, and was so thickly covered with small and large flints (some of them half as large as a child's head) that the field was always called by my sons "the stony field." When they ran down the slope the stones clattered together. I remember doubting whether I should live to see these larger flints covered with vegetable mould and turf. But the smaller stones disappeared before many years had elapsed, as did every one of the larger ones after a time; so that after thirty years (1871) a horse could gallop over the compact turf from one end of the field to the other, and not strike a single stone with his shoes. To anyone who remembered the appearance of the field in 1842, the transformation was wonderful. This was certainly the work of the worms, for though castings were not frequent for several years, yet some were thrown up month after month, and these gradually increased in numbers as the pasture improved. In the year 1871 a trench was dug on the above slope, and the blades of grass were cut off close to the roots, so that the thickness of the turf and of the vegetable mould could be measured accurately. The turf was rather less than half an inch, and the mould, which did not contain any stones, 21/2 inches in thickness. Beneath this lay coarse, clayey earth full of flints, like that in any of the neighboring ploughed fields. This coarse earth easily fell apart from the overlying mould when a split was lifted up. The average rate of accumulation of the mould during the whole thirty years was only .083 inch per year (i.e., nearly one inch in twelve years); but the rate must have been much slower at first, and afterwards considerably quicker.

The transformation in the appearance of this field, which had been effected beneath my eyes, was afterwards rendered the more striking, when I examined in Knole Park a dense forest of lofty beech-trees, beneath which nothing grew. Here the ground was thickly strewed with large, naked stones, and worm-castings were almost wholly absent. Obscure lines and irregularities on the surface indicated that the land had been cultivated some centuries ago. It is probable that a thick wood of young beech-trees sprung up so quickly, that time enough was not allowed for worms to cover up the stone with their castings, before the site became unfitted for their existence. Anyhow, the contrast between the state of the now miscalled "stony field," well stocked with worms, and the present state of the ground beneath the old beech-trees in Knole Park, where worms appeared to be absent, was striking.

A narrow path running across part of my lawn was paved in 1843 with small flag-stones, set edgeways; but worms threw up many castings, and weeds grew thickly between them. During several years the path was weeded and swept; but ultimately the weeds and worms prevailed, and the gardener ceased to sweep, merely moving off the weeds, as often as the lawn was mowed. The path soon became almost covered up, and after several years no trace of it was left. On removing, in 1877, the thin overlaying layer of turf, the small flag-stones, all in their proper places, were found covered by an inch of fine mould.

Two recently published accounts of substances strewed on the surface of pasture-land, having become buried through the action of worms, may be here noticed. The Rev. H. C. Key had a ditch cut in a field, over which coal-ashes had been spread, as it was believed, 18 years before, and on the clean-cut perpendicular sides of the ditch, at a depth of at least 7 inches, there could be seen, for a length of 60 yards, "a distinct, very even, narrow line of coal-ashes, mixed with small coal, perfectly parallel with the top-sward." This parallelism and the length of the section gives interest to the case. Secondly, Mr. Dancer states that crushed bones had been thickly strewed over a field, and "some years afterwards" these were found "several inches below the surface, at a uniform depth." Worms appear to act in the same manner in New Zealand as in Europe; for Professor J. von Haast has described a section near the coast, consisting of mica-schist, "covered by 5 or 6 feet of loess, above which about 12 inches of vegetable soil had accumulated." Between the loess and the mould there was a layer from 3 to 6 inches in thickness, consisting of "cores, implements, flakes, and chips, all manufactured from hard basaltic rock." It is, therefore, probable, that the aborigines, at some former period, had left these objects on the surface, and that they had afterwards been slowly covered up by the castings of worms.

Farmers in England are well aware that objects of all kinds, left on the surface of pasture-lands, after a time disappear, or, as they say, work themselves downwards. How powdered lime, cinders, and heavy stones, can work down, and at the same rate, through the matted roots of a grass-covered surface, is a question which has probably never occurred to them.

_The sinking of great stones through the action of worms._--When a stone of large size and of irregular shape is left on the surface of the ground, it rests, of course, on the more protuberant parts; but worms soon fill up with their castings all the hollow spaces on the lower side; for, as Hensen remarks, they like the shelter of stones. As soon as the hollows are filled up, the worms eject the earth which they have swallowed beyond the circumference of the stones; and thus the surface of the ground is raised all round the stone. As the burrows excavated directly beneath the stone after a time collapse, the stone sinks a little. Hence it is, that boulders which at some ancient period have rolled down from a rocky mountain or cliff on to a meadow at its base, are always somewhat imbedded in the soil; and, when removed, leave an exact impression of their lower surfaces in the under-lying fine mould. If, however, a boulder is of such huge dimensions, that the earth beneath is kept dry, such earth will not be inhabited by worms, and the boulder will not sink into the ground.

A lime-kiln formerly stood in a grass-field near Leith Hill Place, in Surrey, and was pulled down 35 years before my visit; all the loose rubbish had been carted away, excepting three large stones of quartzose sandstone, which it was thought might hereafter be of some use. An old workman remembered that they had been left on a bare surface of broken bricks and mortar, close to the foundations of the kiln; but the whole surrounding surface is now covered with turf and mould. The two largest of these stones had never since been moved; nor could this easily have been done, as, when I had them removed, it was the work of two men with levers. One of these stones, and not the largest, was 64 inches long, 17 inches broad, and from 9 to 10 inches in thickness. Its lower surface was somewhat protuberant in the middle; and this part still rested on broken bricks and mortar, showing the truth of the old workman's account. Beneath the brick rubbish the natural sandy soil, full of fragments of sandstone, was found; and this could have yielded very little, if at all, to the weight of the stone, as might have been expected if the sub-soil had been clay. The surface of the field, for a distance of about 9 inches round the stone, gradually sloped up to it, and close to the stone stood in most places about 4 inches above the surrounding ground. The base of the stone was buried from 1 to 2 inches beneath the general level, and the upper surface projected about 8 inches above this level, or about 4 inches above the sloping border of turf. After the removal of the stone it became evident that one of its pointed ends must at first have stood clear above the ground by some inches, but its upper surface was now on a level with the surrounding turf. When the stone was removed, an exact cast of its lower side, forming a shallow crateriform hollow, was left, the inner surface of which consisted of fine, black mould, excepting where the more protuberant parts rested on the brick-rubbish. A transverse section of this stone, together with its bed, drawn from measurements made after it had been displaced, is here given on a scale of 1/2 inch to a foot (Fig. 2). The turf-covered border which sloped up to the stone, consisted of fine vegetable mould, in one part 7 inches in thickness. This evidently consisted of worm-castings, several of which had been recently ejected. The whole stone had sunk in the thirty-five years, as far as I could judge, about 11/2 inch; and this must have been due to the brick-rubbish beneath the more protuberant parts having been undermined by worms. At this rate, the upper surface of the stone, if it had been left undisturbed, would have sunk to the general level of the field in 247 years; but before this could have occurred, some earth would have been washed down by heavy rain from the castings on the raised border of turf over the upper surface of the stone.

The second stone was larger than the one just described, viz., 67 inches in length, 39 in breadth, and 15 in thickness. The lower surface was nearly flat, so that the worms must soon have been compelled to eject their castings beyond its circumference. The stone as a whole had sunk about 2 inches into the ground. At this rate it would have required 262 years for its upper surface to have sunk to the general level of the field. The upwardly sloping, turf-covered border round the stone was broader than in the last case, viz., from 14 to 16 inches; and why this should be so, I could see no reason. In most parts this border was not so high as in the last case, viz., from 2 to 21/2 inches, but in one place it was as much as 51/2. Its average height close to the stone was probably about 3 inches, and it thinned out to nothing. If so, a layer of fine earth, 15 inches in breadth and 11/2 inch in average thickness, of sufficient length to surround the whole of the much elongated slab, must have been brought up by the worms in chief part from beneath the stone in the course of 35 years. This amount would be amply sufficient to account for its having sunk about 2 inches into the ground; more especially if we bear in mind that a good deal of the finest earth would have been washed by heavy rain from the castings ejected on the sloping border down to the level of the field. Some fresh castings were seen close to the stone. Nevertheless, on digging a large hole to a depth of 18 inches where the stone had lain, only two worms and a few burrows were seen, although the soil was damp and seemed favorable for worms. There were some large colonies of ants beneath the stone, and possibly since their establishment the worms had decreased in number.

The third stone was only about half as large as the others; and two strong boys could together have rolled it over. I have no doubt that it had been rolled over at a moderately recent time, for it now lay at some distance from the two other stones at the bottom of a little adjoining slope. It rested also on fine earth, instead of partly on brick-rubbish. In agreement with this conclusion, the raised surrounding border of turf was only 1 inch high in some parts, and 2 inches in other parts. There were no colonies of ants beneath this stone, and on digging a hole where it had lain, several burrows and worms were found.

At Stonehenge, some of the outer Druidical stones are now prostrate, having fallen at a remote but unknown period; and these have become buried to a moderate depth in the ground. They are surrounded by sloping borders of turf, on which recent castings were seen. Close to one of these fallen stones, which was 17 feet long, 6 feet broad, and 281/2 inches thick, a hole was dug; and here the vegetable mould was at least 91/2 inches in thickness. At this depth a flint was found, and a little higher up on one side of the hole a fragment of glass. The base of the stone lay about 91/2 inches beneath the level of the surrounding ground, and its upper surface 19 inches above the ground.

A hole was also dug close to a second huge stone, which in falling had broken into two pieces; and this must have happened long ago, judging from the weathered aspect of the fractured ends. The base was buried to a depth of 10 inches, as was ascertained by driving an iron skewer horizontally into the ground beneath it. The vegetable mould forming the turf-covered sloping border round the stone, on which many castings had recently been ejected, was 10 inches in thickness; and most of this mould must have been brought up by worms from beneath its base. At a distance of 8 yards from the stone, the mould was only 51/2 inches in thickness (with a piece of tobacco pipe at a depth of 4 inches), and this rested on broken flint and chalk which could not have easily yielded to the pressure or weight of the stone.

A straight rod was fixed horizontally (by the aid of a spirit-level) across a third fallen stone, which was 7 feet 9 inches long; and the contour of the projecting parts and of the adjoining ground, which was not quite level, was thus ascertained, as shown in the accompanying diagram (Fig. 3) on a scale of 1/2 inch to a foot. The turf-covered border sloped up to the stone on one side to a height of 4 inches, and on the opposite side to only 21/2 inches above the general level. A hole was dug on the eastern side, and the base of the stone was here found to lie at a depth of 4 inches beneath the general level of the ground, and of 8 inches beneath the top of the sloping turf-covered border.

Sufficient evidence has now been given showing that small objects left on the surface of the land where worms abound soon get buried, and that large stones sink slowly downwards through the same means. Every step of the process could be followed, from the accidental deposition of a single casting on a small object lying loose on the surface, to its being entangled amidst the matted roots of the turf, and lastly to its being embedded in the mould at various depths beneath the surface. When the same field was re-examined after the interval of a few years, such objects were found at a greater depth than before. The straightness and regularity of the lines formed by the embedded objects, and their parallelism with the surface of the land, are the most striking features of the case; for this parallelism shows how equably the worms must have worked; the result being, partly the effect of the washing down of the fresh castings by rain. The specific gravity of the objects does not affect their rate of sinking, as could be seen by porous cinders, burnt marl, chalk and quartz pebbles, having all sunk to the same depth within the same time. Considering the nature of the sub-stratum, which at Leith Hill Place was sandy soil including many bits of rock, and at Stonehenge, chalk-rubble with broken flints; considering, also, the presence of the turf-covered sloping border of mould round the great fragments of stone at both these places, their sinking does not appear to have been sensibly aided by their weight, though this was considerable.

_On the number of worms which live within a given space._--We will now show, first, what a vast number of worms live unseen by us beneath our feet, and, secondly, the actual weight of the earth which they bring up to the surface within a given space and within a given time. Hensen, who has published so full and interesting an account of the habits of worms, calculates, from the number which he found in a measured space, that there must exist 133,000 living worms in a hectare of land, or 53,767 in an acre. This latter number of worms would weigh 356 pounds, taking Hensen's standard of the weight of a single worm, namely, one gram. It should, however, be noted that this calculation is founded on the numbers found in a garden, and Hensen believes that worms are here twice as numerous as in corn-fields. The above result, astonishing though it be, seems to me credible, judging from the number of worms which I have sometimes seen, and from the number daily destroyed by birds without the species being exterminated. Some barrels of bad ale were left on Mr. Miller's land, in the hope of making vinegar, but the vinegar proved bad, and the barrels were upset. It should be premised that acetic acid is so deadly a poison to worms that Perrier found that a glass rod dipped into this acid and then into a considerable body of water in which worms were immersed, invariably killed them quickly. On the morning after the barrels had been upset, "the heaps of worms which lay dead on the ground were so amazing, that if Mr. Miller had not seen them, he could not have thought it possible for such numbers to have existed in the space." As further evidence of the large number of worms which live in the ground Hensen states that he found in a garden 64 open burrows in a space of 141/2 square feet, that is, 9 in 2 square feet. But the burrows are sometimes much more numerous, for when digging in a grass-field near Maer Hall, I found a cake of dry earth, as large as my two open hands, which was penetrated by seven burrows, as large as goose-quills.

TWO FOPS AMONG THE FISHES

(FROM GLEANINGS FROM NATURE.)[7]

BY W. S. BLATCHLEY.

[7] Copyright by W. S. Blatchley, 1899.

I.--THE RAINBOW DARTER.

"Little fishy in the brook."

Not the one "daddy caught with a hook," but another, too small for the hook, too small for the frying-pan, too small for aught else but beauty, and gracefulness of form; and yet not the young of a larger fish, but full grown of himself. In every brook in the State he may be found, yea, even in the rill, no more than a foot in width, which leads away from the old spring-house on the hillside. You will not find him swimming about like the minnows in the still, deep water of the stream, but where the clear, cold water is rushing rapidly over the stones of a ripple he makes his home. There he rests quietly on the bottom, waiting patiently for his food, the larvae or young of gnats, mosquitoes, and other such insects, to float by.

If you attempt to catch him, or your shadow suddenly frightens him, with a sweep of his broad pectoral or breast fins, he moves quicker than a flash a few feet farther up the stream, and then as suddenly comes to a stop, and resumes his quiet, "thoughtful" attitude. If you persist in your attempt to capture him, he will dart under a small stone or submerged leaf, where, like the foolish ostrich which when pursued hides her head under her wing, no longer seeing you, he thinks himself secure.

On account of the shape of his body, as well as on account of his rapid movements, he has received the surname "darter." Belonging to the group which bears this surname, there are, in the eastern half of the United States, about forty-seven species or kinds, the largest of which, when full grown, measures only about six inches in length, while the smallest species never reaches a length of more than an inch and a half. They all have the same habits, and at least twenty-nine kinds of them are found in Indiana; but the one of which I am writing is much the more common. He is from two to two and a half inches in length, and, like the other members of his family, has two fins on his back; "dorsal" fins they are called by naturalists, the front one of which contains ten short spines. During eight months of the year, the males and females dress alike in a suit of brownish olive which is striped on the sides with ten or twelve narrow, black cross-bars, and more or less blotched on the back with darker spots. But on the first warm days of spring, when the breezes blow up from the gulf, awakening the gypsy in our blood, the little male fish feels, too, their influence, and in him there arises an irresistible desire to "a-courting go." Like most other beings of his sex, he thinks his every-day suit too plain for the important business before him. It will, in his opinion, ne'er catch the eye of his lady love. So he dons one of gaudy colors and from it takes his name,--the rainbow darter,--for in it he is best known, as it not only attracts the attention of his chosen one, but often also that of the wandering naturalist who happens along the stream.

The blackish bars of other seasons are changed to indigo blue, while the space between them assumes a hue of the brightest orange. The fins are broadly edged with blue and have the bases orange, or orange and scarlet, while the cheeks assume the blue and the breast becomes an orange. Clad in this suit he ventures forth on his mission, and if successful, as he almost always is, the two construct a nest of tiny stones in which the eggs of the mother-fish are laid and watched over with jealous care by both parents until in time there issue forth sons destined some day to wear a coat of many colors, and "darters" to be attracted by those coats, as was their mother by the one their father wore.

Although so abundant and so brilliant in the springtime, the rainbow darter is known to few but naturalists. The fishes in which the average country boy is interested are the larger ones--such as the goggle-eye, the sucker, chub, and sunfish--those which, when caught, will fill up the string and tickle the palate.

But there are, let us hope, among our farmers' sons and daughters, some who are learning to take an interest in the objects of nature which are beautiful, as well as in those which are useful. To them I will say, if you wish to see something really pretty, make a seine from an old coffee sack or a piece of mosquito netting, and any day in spring drag two or three ripples of the branch which flows through the wood's pasture, and ten chances to one you will get some "rainbows." By placing them in a fruit jar three-fourths full of clear, cold water, and renewing the water every few hours, they can be kept for several days; but they cannot bear the confinement long, accustomed as they are to the free running stream from which they were taken.

By taking the rainbow as the type of the darter and studying closely its habits, both in captivity and in the streams, much can be learned about a group which, in the words of Dr. S. A. Forbes, "are the mountaineers among fishes. Forced from the populous and fertile valleys of the river beds and lake bottoms, they have taken refuge from their enemies in the rocky highlands where the free waters play in ceaseless torrents, and there they have wrested from stubborn nature a meagre living. Although diminished in size by their continual struggle with the elements, they have developed an activity and hardihood, a vigor of life and a glow of high color almost unknown among the easier livers of the lower lands."

II.--THE LONG-EARED SUNFISH.

Among the most brightly colored of all the fresh-water members of the finny tribe is the long-eared sunfish. When full grown its length is about eight inches and the breadth one-half as much. The color is then a brilliant blue and orange, the former predominating above; the orange on the sides in spots, the blue in wavy, vertical streaks. The cheeks are orange with bright blue stripes; the fins with the membranes orange, and the rays blue. Extending back from the hind margin of each cheek is a conspicuous blackish membrane termed an "ear-flap," which in this species is longer than in any other of the sun-fish family, whence the specific name, _megalotis_, from two Greek words meaning "great" and "ear."

Within the placid pools of the brooks and larger streams of the State this sunfish has its favorite haunts. Mid-summer is the time when its habits can be best observed. On a recent August morn I sat for an hour or longer on the banks of a stream, which flows through a wooded blue-grass pasture, and watched the denizens of its waters. A peaceful calm existed, the water being without a ripple and with scarce the semblance of a flow--the air without the shadow of a breeze. Dragon flies lazily winged their way across the pool, now resting daintily upon a blade of sedge or swamp grass, now dipping the tips of their abdomens beneath the surface of the water while depositing their eggs. The only sounds of nature were the buzz of a bumble-bee feeding among the flowers of the _Brunella_ at my side, and an occasional drawl of a dog-day locust from the branches of the sycamore which threw a grateful shade about me.

The sunfish "hung motionless" in the water, their heads towards me, holding their position only by a slow flapping of their dorsal and pectoral fins. Their nesting time over, their season's labor ended, it was with them, as with many other beings, a time of languor.

These long-eared fishes are the lords and ladies of the respective pools wherein they abide. When they move other smaller fry clear the way. If a worm or gnat, falling upon the surface, tempts them, it is theirs. A leaf falls near them and is seemingly unnoticed--a fly, and how quickly their dormant energy is put into motion. With a dart and a gulp the insect is swallowed, and a new stage of waiting expectancy is ushered in.

How admirably fitted their form for cleaving the water! They often seem to glide rather than propel themselves through its depths. Again, how swiftly the caudal fin moves when with straight unerring motion they dart upon their prey. At times one turns his body sideways, and, with a slow, upward-gliding motion, moves toward some object on the surface which is doubtfully "good to eat." He even takes it into his mouth and then, not having faith in his power to properly digest it, ejects it with force, and turning quickly darts back to the friendly shadow of a boulder beneath whose sides he has, in time of threatened danger, a safe retreat.

I throw a grasshopper into the pool. Like a flash six of the sunfish are after it. One reaches it a tenth of a second in advance of the others, and with a lightning-like gulp, which disturbs the serenity of the surface of the pool, swallows the kicking prey. The energy of the sun's heat and light, stored in grass, transmitted to move muscles in gigantic leaps, will, in a short time, wag a caudal fin and propel the owner through these watery depths.

Years are thus doubtless spent by these long-eared sunfish in a dreamy sort of existence, their energies quickened by the vernal season and growing duller on the approach of winter. Excepting the times when they are tempted by a wriggling worm on some boy's hook, theirs is a life exempt from danger. A kingfisher glancing down from his perch on the bent sycamore limb may, at times, discern them and lessen their ranks; but, methinks, the chub minnows, with fewer spines in their dorsal fins, are more agreeable to the king-fisher's palate. With all the tints of the rainbow gleaming from their sides they move to and fro, the brilliant rulers of these quiet pools.

The king or monarch of those noted was most gorgeously arrayed. In addition to the hues above described, a streak of emerald bordered his dorsal and caudal fins and was bent around the edge of his upper lip--a green mustache, as it were. By tolling them with occasional bits of food I drew him and his retinue close into shore. There, for some time they rested, watching eagerly for additional morsels. As I was leaving I plucked from my sleeve an ant and threw it towards them. A dart, a gurgle, a gulp--the leader had leaped half his length from the water, and the ant was forever gone. The ripples receded and finally disappeared, and the last scene in this tragedy of nature was at an end.

SEA-SLUGS AND CUTTLE-FISH

(FROM A JOURNAL OF RESEARCHES.)

BY CHARLES DARWIN.

I was much interested, on several occasions, by watching the habits of an Octopus, or cuttle-fish. Although common in the pools of water left by the retiring tide, these animals were not easily caught. By means of their long arms and suckers, they could drag their bodies into very narrow crevices; and when thus fixed, it required great force to remove them. At other times they darted, tail first, with the rapidity of an arrow, from one side of the pool to the other, at the same instant discoloring the water with a dark chestnut-brown ink. These animals also escape detection by a very extraordinary, chameleon-like power of changing their color. They appear to vary their tints according to the nature of the ground over which they pass: when in deep water, their general shade was brownish-purple, but when placed on the land, or in shallow water, this dark tint changed into one of a yellowish green. The color, examined more carefully, was a French gray, with numerous minute spots of bright yellow: the former of these varied in intensity; the latter entirely disappeared and appeared again by turns. These changes were effected in such a manner, that clouds, varying in tint between a hyacinth red and a chestnut brown, were continually passing over the body. Any part, being subjected to a slight shock of galvanism, became almost black: a similar effect, but in a less degree, was produced by scratching the skin with a needle. These clouds, or blushes as they may be called, are said to be produced by the alternate contraction and expansion of minute vescicles containing variously colored fluids.

This cuttle-fish displayed its chameleon-like power both during the act of swimming and whilst remaining stationary at the bottom. I was much amused by the various arts to escape detection used by one individual, which seemed fully aware that I was watching it. Remaining for a time motionless, it would then stealthily advance an inch or two, like a cat after a mouse; sometimes changing its color: it thus proceeded, till having gained a deeper part, it darted away, leaving a dusky train of ink to hide the hole into which it had crawled.

While looking for marine animals, with my head about two feet above the rocky shore, I was more than once saluted by a jet of water, accompanied by a slight grating noise. At first I could not think what it was, but afterwards I found out that it was this cuttle-fish, which, though concealed in a hole, thus often led me to its discovery. That it possesses the power of ejecting water there is no doubt, and it appeared to me that it could certainly take good aim by directing the tube or siphon on the upper side of its body. From the difficulty which these animals have in carrying their heads, they cannot crawl with ease when placed on the ground. I observed that one which I kept in the cabin was slightly phosphorescent in the dark.

THE COW-FISH

(FROM TRAVELS ON THE AMAZON.)

BY SIR ALFRED RUSSELL WALLACE.

It was a female, about six feet long, and nearly five in circumference in the thickest part. The body is perfectly smooth, and without any projections or inequalities, changing into a horizontal semicircular flat tail, with no appearance whatever of hind limbs. There is no distinct neck; the head is not very large, and is terminated by a large mouth and fleshy lips, somewhat resembling those of a cow. There are stiff bristles on the lips, and a few distantly scattered hairs over the body. Behind the head are two powerful oval fins, and just beneath them are the breasts, from which, on pressure being applied, flows a stream of beautiful white milk. The ears are minute holes, and the eyes very small. The color is a dusky lead, with some large pinkish-white marbled blotches on the belly. The skin is about an inch thick on the back, and a quarter of an inch on the belly. Beneath the skin is a layer of fat of a greater or less thickness, generally about an inch, which is boiled down to make an oil used for light and for cooking. The intestines are very voluminous, the heart about the size of a sheep's, and the lungs about two feet long, and six or seven inches wide, very cellular and spongy, and can be blown out like a bladder. The skull is large and solid, with no front teeth; the vertebrae extend to the very tip of the tail, but show no rudiments of posterior limbs; the fore limbs, on the contrary, are very highly developed, the bones exactly corresponding to those of the human arm, having even the five fingers, with every joint distinct, yet enclosed in a stiff inflexible skin, where not a joint can have any motion.

The cow-fish feeds on grass at the borders of the rivers and lakes, and swims quickly with the tail and paddles; and though the external organs of sight and hearing are so imperfect, these senses are said by the hunters to be remarkably acute, and to render necessary all their caution and skill to capture the animals. They bring forth one, or rarely two, young ones, which they clasp in their arms or paddles while giving suck. They are harpooned or caught in a strong net, at the narrow entrance of a lake or stream. Each yields from five to twenty-five gallons of oil. The flesh is very good, being something between beef and pork, and this one furnished us with several meals, and was an agreeable change from our fish diet.

OLD RATTLER AND THE KING SNAKE[8]

BY DAVID STARR JORDAN.

PRESIDENT OF LELAND STANFORD, JUNIOR, UNIVERSITY.

[8] From _The Popular Science Monthly_ by permission.

"I only know thee humble, bold, Haughty, with miseries untold, And the old curse that left thee cold, And drove thee ever to the sun On blistering rocks ... Thou whose fame Searchest the grass with tongue of flame, Making all creatures seem thy game, When the whole woods before thee run, Asked but--when all is said and done-- To lie, untrodden, in the sun!" --BRET HARTE.

Old Rattler was a snake, of course, and he lives in the King's River Canon, high up and down deep in the mountains of California.

He had a hole behind and below a large, flat granite rock, not far from the river, and he called it his home; for in it he slept all night and all winter, but when the sun came back in the spring and took the frost out of the air and the rocks, then he crawled out to lie until he got warm. The stream was clear and swift in the canon, the waterfalls sang in the side gulch of Roaring River, the wind rustled in the long needles of the yellow pines, and the birds called to their mates in the branches. But Old Rattler did not care for such things. He was just a snake, you know, and his neighbors did not think him a good snake at that, for he was surly and silent, and his big, three-cornered, "coffin-shaped" head, set on a slim, flat neck, was very ugly to see. But when he opened his mouth he was uglier still, for in his upper jaw he had two long fangs, and each one was filled with deadly poison. His vicious old head was covered with gray and wrinkled scales, and his black, beadlike eyes snapped when he opened his mouth to find out whether his fangs were both in working order.

Old Rattler was pretty stiff when he first came from his hole on the morning of this story. He had lain all night coiled up like a rope among the rocks, and his tail felt very cold. But the glad sun warmed the cockles of his heart, and in an hour or two he became limber, and this made him happy in his snaky fashion. But, being warm, he began to be hungry, for it had been a whole month since he had eaten anything. When the first new moon of August came, his skin loosened everywhere and slipped down over his eyes like a veil, so that he could see nothing about him, and could not hunt for frogs by the river, nor for chipmunks among the trees. But with the new moon of September all this was over. The rusty brown old coat was changed for a new suit of gray and black, and the diamond-shaped checkers all over it were clean and shiny as a set of new clothes out to be.

There was a little striped chipmunk running up and down the sugar-pine tree over his head, pursing his little mouth and throwing himself into pretty attitudes, as though he were the centre of an admiring audience, and Old Rattler kept a steady eye on him. But he was in no hurry about it all. He must first get the kinks out of his neck, and the cold cramps from his tail. There was an old curse on his family, so the other beasts had heard, that kept him always cold, and his tail was the coldest part of all. So he shook it a little, just to show that it was growing limber, and the bone clappers on the end rustled with a sharp, angry noise. Fifteen rattles he had in all--fifteen and a button--and to have so many showed that he was no common member of his hated family. Then he shook his tail again, and more sharply. This was to show all the world that he, Old Rattler, was wide awake, and whoever stepped on him would better look out. Then all the big beasts and little beasts who heard the noise fled away just as fast as ever they could; and to run away was the best thing they could do, for when Old Rattler struck one of them with his fangs all was over with him. So there were many in the canon, beasts and birds and snakes too, who hated Old Rattler, but only a few dared face him. And one of these was Glittershield, whom men call the King of Snakes, and in a minute I shall tell you why.

And when Old Rattler was doing all that I have said, the King Snake lay low on a bed of pine needles, behind a bunch of fern, and watched him with keen, sharp eye. The angry buzz of Rattler's tail, which scared the chipmunks and the bullfrogs and all the rest of the beast folk, was music for Glittershield. He was a snake, too, and snakes understand some things better than any of the rest of us.

Glittershield was slim and wiry in his body, as long as Old Rattler himself, but not so large around. His coat was smooth and glossy, not rough and wrinkly like Old Rattler's, and his upraised head was small and pretty--for a snake. He was the best dressed of all his kind, and he looked his finest as he faced Old Rattler. His head was shiny black, his throat and neck as white as milk while all down his body to the end of his tail he was painted with rings, first white, then black, then crimson, and every ring was bright as if it had just been freshly polished that very day.

So the King Snake passed the sheltering fern and came right up to Old Rattler. Rattler opened his sleepy eyes, threw himself on guard with a snap and a buzz, and shook his bony clappers savagely. But the King of Snakes was not afraid. Every snake has a weak spot somewhere, and that is the place to strike him. If he hadn't a weak spot no one else could live about him, and then, perhaps he would starve to death at last. If he had not some strong points, where no one could harm him, he couldn't live himself.

As the black crest rose, Old Rattler's tail grew cold, his head dropped, his mouth closed, he straightened out his coil, and staggered helplessly toward his hole.

This was the chance for Glittershield. With a dash so swift that all the rings on his body--red, white, and black--melted into one purple flash, he seized Old Rattler by his throat. He carried no weapons, to be sure. He had neither fangs nor venom. He won his victories by force and dash, not by mean advantage. He was quick and strong, and his little hooked teeth held like the claws of a hawk. Old Rattler closed his mouth because he couldn't help it, and the fangs he could not use were folded back against the roof of his jaw.

The King Snake leaped forward, wound his body in a "love-knot" around Old Rattler's neck, took a "half-hitch" with his tail about the stomach, while the rest of his body lay in a curve like the letter S between the two knots. Then all he had to do was to stiffen up his muscles, and Old Rattler's backbone was snapped off at the neck.

All that remained to Glittershield was to swallow his enemy. First he rubbed his lips all over the body, from the head to the tail, till it was slippery with slime. Then he opened his mouth very wide, with a huge snaky yawn, and face to face he began on Old Rattler. The ugly head was hard to manage, but, after much straining, he clasped his jaws around it, and the venom trickled down his throat like some fiery sauce. Slowly head and neck and body disappeared, and the tail wriggled despairingly, for the tail of the snake folk can not die till sundown, and when it went at last the fifteen rattles and the button were keeping up an angry buzz. And all night long the King of Snakes, twice as big as he ought to be, lay gorged and motionless upon Old Rattler's rock.

And in the morning the little chipmunk ran out on a limb above him, pursed up his lips, and made all kinds of faces, as much as to say, "I did all this, and the whole world was watching while I did it."

THE STORY OF A STRANGE LAND

(FROM SCIENCE SKETCHES.)[9]

BY DAVID STARR JORDAN.

PRESIDENT OF LELAND STANFORD, JUNIOR, UNIVERSITY.

[9] Copyright, 1896, by A. C. Mclurg & Co.

"In one strange land, And a long way from home, I heard a mighty rumbling, and I couldn't tell where." --NEGRO MELODY.

It happened a long time ago, it may be fifty thousand years in round numbers, or it may have been twice as many, that a strange thing took place in the heart of the Great Mountains. It was in the middle of the Pliocene epoch, a long, dull time that seemed as if it would never come to an end. There was then on the east side of the Great Divide a deep, rocky basin surrounded by high walls of granite gashed to the base by the wash of many streams. In this basin, we know not how--for the records all are burned or buried--the crust of the earth was broken, and a great outflow of melted larva surged up from below. This was no ordinary eruption, but a mighty outbreak of the earth's imprisoned forces. The steady stream of lava filled the whole mountain basin and ran out over its sides, covering the country all around so deeply that it has never been seen since. More than four thousand square miles of land lay buried under melted rock. No one can tell how deep the lava is, for no one has ever seen the bottom. Within its bed are deep clefts whose ragged walls descend to the depth of twelve hundred feet, and yet give no glimpse of the granite below, while at their side are mountains of lava whose crags tower a mile above the bottom of the ravines.

At last, after many years or centuries--time does not count for much in these Tertiary days--the flow of melted lava ceased. Its surface cooled, leaving a high, uneven plain, black and desolate, a hard, cold crust over a fiery and smoldering interior. About the crater lay great ropes and rolls of the slowly hardening lava, looking like knots and tangles of gigantic reptiles of some horrible extinct sort. There was neither grass nor trees, nor life of any sort. Nothing could grow in the coarse, black stone. The rivers and brooks had long since vanished in steam, the fishes were all dead, and the birds had flown away. The whole region wore the aspect of the desolation of death.

But to let land go to waste is no part of Mother Nature's plan. So even this far-off corner of her domain was made ready for settlement. In the winter she sifted snow on the cold black plain, and in the summer the snow melted into a multitude of brooks and springs. The brooks gradually wore paths and furrows down the large bed, and the sands which they washed from one place they piled up in another. The winds blew the seeds of grasses about, and willows and aspens crept up the mountain-sides. Then came the squirrels, scattering the nuts of the pine. Other seeds came too, in other ways, till at last the barren hillside was no longer barren.

The brooks ran over the surface of the crust undisturbed by the fires within, and were clear and cold as mountain brooks should be; but the rain and melted snow will never all remain on the surface. Some of it falls into cracks or joints or porous places in the rock, and from this come underground streams or springs. But in this region a stream could not run long underground without coming in contact with the old still-burning fires. When a crust is formed over the lava, it cools very slowly. When the crust is a rod or two deep, the lava within is almost as well protected as if it were at the center of the earth.

Whenever the water came down into the fire, the hot rocks would be furious with indignation, and tearing the water to atoms they would throw it back to the surface as steam. Then the explosive force of the steam would in turn tear up the rocks, making still larger the hole through which the water came. When the rocks were very hot, a little water upon them would make a terrible commotion like the shock of an earthquake. When much water came down, it would hiss and boil high in the air, as it tried to break the cushion of steam which came between it and the lava.

And all this went on in hundreds of places and maybe for thousands of years. The hot rocks glowed and sweltered in the ground, and the cold snow-water crept after them closer and closer, while more and more vigorously the rocks resented the intrusion. Sometimes the water would go down in a mass through a cleft, when it would be hurled bodily the very way it came. At other times the water came down little by little, insinuating itself into many places at once. Then the hot rocks threw it back in many little honeycomb channels, and by the spreading of these channels the rocks were at last crumbled to pieces. The hard black lava on the glass-like obsidian were changed to white kaolin as soft and powdery as chalk. And as the water fought its way, gaining a little every year, steadily working between the joints in the enemy's armor and as surely being thrown back with violence if it penetrated too far, the animals and the plants followed in the wake of the water, and took possession of the territory as fast as it was won.

At last the Pliocene times were over, for all times come to an end. The one sure thing on the earth is the certainty of change. With the change of time came on the earth's great winter. The snow-drifts on the lava were piled up mountain-high. Snow is but ice gathered in little fragments which will grow solid under pressure. As the snow accumulated it began to move, forming great rivers of ice which ran down the courses of the stream. And as these slowly moving, gigantic ice-rivers tore away huge blocks of lava and pushed them down the mountain-sides, where the rocks had been softened by the action of steam, the ice wore out deep valleys, and everything that it touched was smoothed and polished. The winter of the great Ice age lasted a very long time, many thousands of years; but, long as it was and long ago, it came at last to an end--not to a full stop, of course, for even now, some of its snow still lingers on the highest peaks that surround the lava-beds.

Then the winters grew shorter and the summers longer. The south winds blew and the ice melted away, first from the plain and then from the mountains. The water ran down the sides of the lava-bed, cutting deep gorges or canons, so deep that the sun can hardly see the bottom. And into the joints and clefts of the rocks more and more water went, to be hurled back with greater and greater violence, for all the waters of all the snow cannot put out a mile deep of fire.

In the old depressions where the ice had chiselled away the softer rocks, there were formed lakes of the standing water, and one of these was more than thirty miles long, winding in and out among the mountain-ridges. In the lake bottom the water soaked through down to the hot lava below, from which it was thrown boiling back to the surface again, fountains of scalding water in the icy lake.

The cold Ice age has killed all the plants in the region; and it had driven off the animals that could be driven, and had then buried the rest. But when the snow was gone the creatures all came back again. Grass and meadow-flowers of a hundred kinds came up from the valleys below. The willow and the aspen took their place again by the brook-side, and the red fir and the mountain pine covered the hills with their sombre green. The birds came back. The wild goose swam and screamed, and the winter wren caroled his bright song--loudest when there seemed least cause for rejoicing. The beaver cut his timber and patiently worked at his dams. The thriftless porcupine destroyed a tree for every morning meal. The gray jay, the "camp robber," followed the Indians about in hope that some forgotten piece of meat or of boiled root might fall to his share; while the buffalo, the bear, and the elk each carried on his affairs in his own way, as did a host of lesser animals, all of whom rejoiced when this snow-bound region was at last opened for settlement. Time went on. The water and the fire were every day in mortal struggle, and always when the water was thrown back repulsed, it renewed the contest as vigorously as before. The fire retreated, leaving great stretches of land to its enemy, that it might concentrate its strength where its strength was greatest. And the water steadily gained, for the great ocean ever lay behind it. So for century after century they wrestled with each other, the water, the fire, the snow, the animals and the plants. But the fishes who had once lived in the mountain torrents were no longer there. They had been boiled and frozen, and in one way or another destroyed or driven away. Now they could not get back. Every stream had its canon, and in each canon was a waterfall so high that no trout could leap up. Although they used to try it every day, not one ever succeeded.

So it went on. A great many things happened in other parts of the world. America had been discovered and the colonies were feeling their way toward the Pacific Ocean. And in the vanguard was the famous expedition of Lewis and Clarke, which went overland to the mouth of the river Columbia. John Colter was a hunter in this expedition, and by some chance he went across the mountains on the old trail of the Nez Perces Indians which leads across the Divide from the Missouri waters to those of the Columbia. When he came back from the Nez Perces trail he told most wonderful tales of what he had seen at the head of the Missouri. There were cataracts of scalding water which shot straight up into the air; there were blue ponds hot enough to boil fish; there were springs that came up snorting and steaming, and which would turn trees into stone; the woods were full of holes from which issued streams of sulphur; there were canons of untold depth with walls of ashes full of holes which let off steam like a locomotive, and there were springs which looked peaceful enough, but which at times, would burst like a bomb.

In short, every one laughed at Colter and his yarns, and this place where all lies were true was familiarly known as "Colter's Hell." But for once John Colter told the truth, and the truth could not easily be exaggerated. But no one believed him. When others who afterwards followed him over the Nez Perces trail told the same stories, people said they had been up to "Colter's Hell" and had learned to lie.

But, as time passed, other men told what they had seen, until, in 1870, a sort of official survey was made under the lead of Washburne and Doane. This party got the general bearings of the region, named many of the mountains, and found so much of interest that the next year Dr. Hayden, the United States Geologist, sent out a party for systematic exploration. The Hayden party came up from Colorado on horseback, through dense and tangled forests, across mountain torrents, and other craggy peaks. The story of this expedition has been most charmingly told by its youngest member, another John Coulter. Professor Coulter was the botanist of the survey, and he won the first of his many laurels on this expedition. In 1872, acting on Hayden's report, Congress took the matter in hand and set apart this whole region as a "public park or pleasuring ground for the benefit and enjoyment of the people," and such it remains to this day.

But, while only of late this region has had a public history, the long-forgotten years between the Glacial period and the expedition of Lewis and Clarke were not without interest in the history of the trout. For all these years the fishes have been trying to mount the waterfalls in order to ascend to the plateau above. Year after year, as the spawning-time came on, they leaped against the falls of the Gardiner, the Gibbon, and the Firehole Rivers, but only to fall back impotent in the pools at their bases. But the mightiest cataract of all, the great falls of the Yellowstone, they finally conquered, and in this way it was done: not by the trout of the Yellowstone River, but by their brothers on the other side of the Divide. These followed up the Columbia to the head-waters of the Snake River, its great tributary, past the beautiful Heart Lake, and then on to the stream now called Pacific Creek, which rises on the very crest of the Divide. In the space between this stream, which flows west to help form the Snake River, and a smaller stream now called Atlantic Creek, flowing down the east slope of the Divide, the great chain of the Rocky Mountains shrinks to a narrow plateau of damp meadow, not a fourth of a mile in width; and some years, when the snows are heavy and melt late in the spring, this whole region is covered with standing water. The trout had bided their time until they found it so, and now they were ready for action. Before the water was drained they had crossed the Divide and were descending on the Atlantic side toward the Yellowstone Lake. As the days went by, this colony of bold trout spirits grew and multiplied and filled the waters of the great clear lake, where their descendants remain to this day. And no other fishes--not the chub, nor the sucker, nor the white-fish, nor the minnow, nor the blob--had ever climbed Pacific Creek. None of them were able to follow where the trout had gone, and none of them have ever been seen in the Yellowstone Lake. What the trout had done in this lake--their victories and defeats, their struggles with the bears and pelicans, and with the terrible worm, joint enemy of trout and pelicans alike--must be left for another story.

So the trout climbed the Yellowstone Falls by way of the back staircase. For all we know, they have gone down it on the other side. And in a similar way, by stealing over from Blacktail Deer Creek, they overcame the Undine Falls in Lava Creek and passed its steep obsidian walls, which not all the fishes in the world could climb.

In the Gibbon River the cataracts have proved to the trout an impassible barrier; but, strangely enough, its despised associate, the sluggish, chunky blob, the little soft-bodied, smooth, black tadpole-like fellow, with twinkling eyes and a voracious appetite--a fish who cannot leap at all--has crossed this barrier. Hundreds of blob live under the stones in the upper reaches of the stream, the only fish in the Gibbon waters. There he is, and it is a standing puzzle even to himself to know how he got there. We might imagine, perhaps, that some far-off ancestor, some ancient Queen of the Blobs, was seized by an osprey and carried away in the air. Perhaps an eagle was watching and forced the osprey to give up its prey. Perhaps in the struggle the blob escaped, falling into the river above the falls, to form the beginning of the future colony. At any rate, there is the great impassable waterfall, the blob above it and below. The osprey has its nest on a broken pine tree, above the cataract, and its tyrant master, the bald eagle, watches it from a still higher crag whenever it goes fishing.

Two years ago the Hon. Marshall McDonald, whose duty as United States Fish Commissioner it is to look after the fishes wherever they may be, sent me to this country to see what could be done for his wards. It was a proud day when I set out from Mammoth Hot Springs astride a black cayuse, or Indian pony, which answered to the name of Jump, followed by a long train of sixteen other cayuses of every variety of color and character, the most notable of all being a white pony called Tinker. At some remote and unidentified period of her life she had bucked and killed a tradesman who bestrode her against her will, and thereby, as in the old Norse legends, she has inherited his strength, his wickedness, and his name. And when, after many adventures, I came back from this strange land and told the story of its fishes other men were sent out from Washington with nets and buckets. They gathered up the trout and carried them to the rivers above the falls, and now all the brooks and pools of the old lava-bed, the fairest streams in the world, are full of their natural inhabitants.

THE COLORS OF ANIMALS

(FROM CHAPTERS IN POPULAR NATURAL HISTORY.)

BY SIR JOHN LUBBOCK, BART., M.P., F.B.S., ETC.

The color of animals is by no means a matter of chance; it depends on many considerations, but in the majority of cases tends to protect the animal from danger by rendering it less conspicuous. Perhaps it may be said that if coloring is mainly protective, there ought to be but few brightly colored animals. There are, however, not a few cases in which vivid colors are themselves protective. The kingfisher itself, though so brightly colored, is by no means easy to see. The blue harmonizes with the water, and the bird as it darts along the stream looks almost like a flash of sunlight; besides which, protection is not the only consideration. Let us now consider the prevalent colors of animals and see how far they support the rule.

Desert animals are generally the color of the desert. Thus, for instance, the lion, the antelope, and the wild ass are all sand-colored. "Indeed," says Canon Tristram, "in the desert, where neither trees, brushwood, nor even undulation of the surface afford the slightest protection to its foes, a modification of color which shall be assimilated to that of the surrounding country is absolutely necessary. Hence, without exception, the upper plumage of every bird, whether lark, chat, sylvain, or sand grouse, and also the fur of all the smaller mammals and the skin of all the snakes and lizards, is of one uniform sand color."

It is interesting to note that, while the lion is sand-colored like the desert, the long, upright, yellow stripes of the tiger make it very difficult to see the animal among the long dry grasses of the Indian jungles in which it lives. The leopard, again, and other tree cats are generally marked with spots which resemble gleams of light glancing through the leaves.

The colors of birds are in many cases perhaps connected with the position and mode of construction of their nests. Thus, we know that hen birds are generally less brightly colored than the cocks, and this is partly, perhaps, because bright colors would be a danger to the hens while sitting on their eggs. When the nest is placed underground or in the hole of a tree, etc., we find it no longer to be such an invariable rule that the hen bird is dull-colored; but, on the contrary, she is then often as gaily colored as the male. Such, for instance, is the case with the hen kingfisher, which is one of the brightest of British birds and one of the very few which make their nests underground; the hen woodpecker, which is also gaily colored and builds in hollow trees, forms a second instance.

In the few cases where the hens are as conspicuously colored as the cocks, and yet the nest is open to view, we generally find that the hens are strong, pugnacious birds, and well able to defend themselves. There are even instances, though these are comparatively rare, in which the hens are more brilliantly colored than the cocks; and it is an interesting fact that it is then the cocks, and not the hens, which hatch the eggs.

It therefore seems to be a rule, with very few exceptions, that when both the cocks and hens are of strikingly gay or conspicuous colors, the nest is such as to conceal the sitting bird; while, whenever there is a striking contrast of colors, the nest is open and the sitting bird exposed to view.

Again, most fishes are dark above and pale below. This points to the same fact, for when one looks down into the dark water, the dark color of their backs renders them the less easy to distinguish; while, to an enemy looking up from below, the pale belly would be less conspicuous against the light of the sky. Those fishes which live deep down in the depths of the ocean present no such contrast between the upper and under surface. Many of the smaller animals which live in the sea are as transparent as glass, and are consequently very difficult to distinguish.

It is sometimes said that if animals were really colored with reference to concealment, sheep would be green, like grass. This, however, is quite a mistake. If they were green they would really be more easy to see. In the gray of the morning and the evening twilight, just the time when wild animals generally feed, gray and stone colors are most difficult to distinguish. Sheep were originally mountain animals, and every one who has ever been on a mountain-side knows how difficult it is to distinguish a sheep, at some distance, from a mass of stone or rock.

It is, again, a great advantage to the rabbit and hare to be colored like earth; black or white rabbits are more easy to see, and consequently more likely to be killed. This, however, does not apply to those which are kept in captivity, and we know that tame rabbits are often black and white. Again, in the far north, where for months together the ground is covered with snow, the white color, which would be a danger here, becomes an advantage; and many Arctic animals, like the polar bear and polar hare, are white, while others, such as the mountain hare and ptarmigan, change their color, being brown in summer and white in winter. So are the Arctic fox and the ermine, to whom it is then an advantage to be white, not to avoid danger, but in order that they may be the more easily able to steal unperceived upon their prey.

Many of the cases in which certain insects escape danger by their similarity to plants are well known; the leaf insect and the walking-stick insect are familiar and most remarkable cases. The larvae of insects afford, also, many interesting examples, and in other respects teach us, indeed, many instructive lessons. It would be a great mistake to regard them as merely preparatory stages in the development of the perfect insect. They are much more than this, for external circumstances act on the larvae, as well as on the perfect insect: both, therefore, are liable to adaptation. In fact, the modifications which insect larvae undergo may be divided into two kinds--developmental, or those which tend to approximation to the mature form; and adaptational or adaptive, those which tend to suit them to their own mode of life.

It is a remarkable fact, that the forms of larvae do not depend on those of the mature insect. In many cases, for instance, very similar larvae produce extremely dissimilar insects. In other cases, similar, or comparatively similar, perfect insects have very dissimilar larvae. Indeed, a classification of insects founded on larva would be quite different from that founded on the perfect insects. The group to which the bees, wasps, and ants belong, for instance, and which, so far as the perfect insects are concerned, form a very natural division, would be divided into two; or rather one portion of them--namely, the saw-flies--would be united to the butterflies and moths. Now, why do the larvae of saw-flies differ from those of their allies, and resemble those of butterflies and moths? It is because their habits differ from those of ants and bees, and they feed on leaves like ordinary caterpillars.

In some cases the form changes considerably during the larval state. From this point of view, the transformations of a small beetle, called _Sitaris_, which have been carefully observed by M. Fabre, are peculiarly interesting.

The genus Sitaris, which is allied to the blister-fly and to the oil-beetle, is parasitic on a kind of solitary bee which excavates subterranean galleries, each leading to a cell. The eggs of the beetle, which are deposited at the entrance of the galleries made by the bees, are hatched at the end of September or beginning of October, and we might not unnaturally expect that the young larvae, which are active little creatures with six serviceable legs, would at once eat their way into the cells of the bee. No such thing: till the month of April following they remain without leaving their birthplace, and consequently without food; nor do they in this long time change either in form or size. M. Fabre ascertained this, not only by examining the burrow of the bees, but also by direct observations of some young larvae kept in captivity. In April, however, his captives at last awoke from their long lethargy, and hurried anxiously about their prisons. Naturally inferring that they were in search of food, M. Fabre supposed that this would consist either of the larvae or pupae of the bee, or of the honey with which it stores its cell. All three were tried without success. The first two were neglected; and the larvae, when placed on the latter, either hurried away or perished in the attempt, being evidently unable to deal with the sticky substance. M. Fabre was in despair. The first ray of light came to him from our countryman Newport, who ascertained that a small parasite found on one of the wild bees was, in fact, the larva of the oil-beetle. The larvae of Sitaris much resembled this larva. Acting on this hint, M. Fabre examined many specimens of the bee, and found on them at last the larvae of his Sitaris. The males of the bee emerge from the pupae sooner than the females, and M. Fabre ascertained that, as they come out of their galleries, the little Sitaris larvae fasten upon them. Not, however, for long: instinct teaches them that they are not yet in the straight path of development; and, watching their opportunity, they pass from the male to the female bee. Guided by these indications, M. Fabre examined several cells of the bee; in some, the egg of the bee floated by itself on the surface of the honey; in others, on the egg, as on a raft, sat the still more minute larva of the Sitaris. The mystery was solved. At the moment when the egg is laid, the Sitaris larva springs upon it. Even while the poor mother is carefully fastening up her cell, her mortal enemy is beginning to devour her offspring; for the egg of the bee serves not only as a raft, but as a repast. The honey, which is enough for either, would be too little for both; and the Sitaris, therefore, at its first meal, relieves itself from its only rival. After eight days the egg is consumed, and on the empty shell the Sitaris undergoes its first transformation, and makes its appearance in a very different form.

The honey, which was fatal before, is now necessary--the activity, which before was necessary, is now useless; consequently, with the change of skin, the active, slim larva changes into a white fleshy grub, so organized as to float on the surface of the honey, with the mouth beneath and the breathing-holes above the surface; for insects breathe, not as we do through the mouth, but through a row of holes arranged along the side. In this state it remains until the honey is consumed; then the animal contracts, and detaches itself from its skin, within which the further transformations take place. In the next stage the larva has a solid corneous envelope and an oval shape, and, in its color, consistency, and immobility, resembles the chrysalis of a fly. The time passed in this condition varies much. When it has elapsed, the animal moults again, again changes its form; after this, it becomes a pupa, without any remarkable peculiarities. Finally, after these wonderful changes and adventures, in the month of August the perfect beetle makes its appearance.

In fact, whenever in any group we find differences in form or color, we shall always find them associated with differences in habit. Let us take the case of Caterpillars. The prevailing color of caterpillars is green, like that of leaves. The value of this to the young insect, the protection it affords, are obvious. We must all have observed how difficult it is to distinguish small green caterpillars from the leaves on which they feed. When, however, they become somewhat larger, their form betrays them, and it is important that there should be certain marks to divert the eye from the outlines of the body. This is effected, and much protection is given, by longitudinal lines (Fig. 1), which accordingly are found on a great many caterpillars. These lines, both in color and thickness, much resemble some of the lines on leaves (those, for instance, of grasses), and also the streaks of shadow which occur among foliage. If this be the explanation of them, then they ought to be wanting, as a general rule, in very small caterpillars, and should prevail most among those which feed on or among grasses.

Now, similar lines occur on a great number of caterpillars belonging to most different groups of butterflies and moths, as you may see by turning over the illustrations of any monograph of the group. They exist among the Hawk-moths--as, for instance, in the Humming-bird Hawk-moth; they occur in many butterflies, especially in those which feed on grass; and in many moths. But you will find that the smallest caterpillars rarely possess these white streaks. As regards the second point, also, the streaks are generally wanting in caterpillars which feed on large-leaved plants. The _Satyridae_, on the contrary, all possess them, and all live on grass. In fact we may say, as a general rule, that these longitudinal streaks only occur on caterpillars which live on or among narrow-leaved plants. As the insect grows, these lines often disappear on certain segments, and are replaced by diagonal lines. These diagonal lines (Fig. 2) occur in a great many caterpillars, belonging to the most distinct families of butterflies and moths. They come off just at the same angle as the ribs of leaves, and resemble them very much in general effect. They occur also especially on species which feed on large-leaved plants; and I believe I may say that though a great many species of caterpillars present these lines, they rarely, if ever, occur in species which live on grass; while, on the contrary, they are very frequent in those species which live on large-leaved plants.

It might at first be objected to this view that there are many cases, as in the Elephant-Hawk-moth, in which caterpillars have both. A little consideration, however, will explain this. In small caterpillars these oblique lines would be useless, because they must have some relation, not only in color, but in their distance apart, to the ribs of the leaves. Hence, while there are a great many species which have, longitudinal lines when young, and diagonal ones when they are older and larger, there is not, I believe, a single one which begins with diagonal lines, and then replaces them with longitudinal ones. The disappearance of the longitudinal lines on those segments which have diagonal ones, is striking, where the lines are marked. It is an advantage, because white lines crossing one another at such an angle have no relation to anything which occurs in plants, and would make the creature more conspicuous. When, therefore, the diagonal lines are developed, the longitudinal ones often disappear. There is one other point in connection with these diagonal lines to which I must call your attention.

In many species they are white, but in some cases--as, for instance, in the beautiful green caterpillar of the Privet-Hawk-moth--the white streak is accompanied by a colored one, in that case lilac. At first we might think that this would be a disadvantage, as tending to make the caterpillar more conspicuous; and in fact, if we put one in full view--for instance, out on a table--and focus the eye on it, the colored lines are very striking. But we must remember that the habit of the insect is to sit on the lower side of the leaf, generally near the middle rib, and in the subdued light of such a situation, especially if the eye be not looking exactly at them, the colored lines beautifully simulate a line of soft shadow, such as must always accompany a strong rib; and I need not tell any artist that the shadows of yellowish-green must be purplish. Moreover, any one who has ever found one of these large caterpillars will, I am sure, agree with me that it is surprising, when we consider their size and conspicuous coloring, how difficult it is to see them.

But though the prevailing color of caterpillars is green, there are numerous exceptions. In one great family of moths the prevailing color is brown. These caterpillars, however, escape observation by their great similarity to brown twigs--a resemblance which is heightened by their peculiar attitudes, and in many cases by the existence of warts or protuberances, which look like buds. Some, however, even of these caterpillars, when very young, are green. Again, some caterpillars are white. These feed on and burrow in wood. The Ringlet Butterfly also has whitish caterpillars, and this may at first sight appear to contradict the rule, since it feeds on grass. Its habit is, however, to keep at the roots by day, and feed only at night.

In various genera we find Black caterpillars, which are of course very conspicuous, and, so far as I know, not distasteful to birds. In such cases, however, it will be found that they are covered with hairs or spines, which protect them from most birds. In these species the bold dark color may be an advantage, by rendering the hair more conspicuous. Many caterpillars are black and hairy, but I do not know any large caterpillar which is black and smooth.

Brown caterpillars, also, are frequently protected by hairs or spines in the same way; but, unlike black ones, they are frequently naked. These fall into two principal categories: firstly, those which, like the Geometridae, put themselves into peculiar and stiff attitudes, so that in form, color, and position they closely resemble bits of dry stick; and, secondly, those which feed on low plants, concealing themselves on the ground by day, and only coming out in the dark.

Yellow and yellowish-green caterpillars are abundant, and their color is a protection. Red and blue, on the contrary, are much less common colors, and are generally present as spots.

Moreover, caterpillars with red lines or spots are generally hairy, and this for the reason given above. Such species, therefore, would be avoided by birds. There are, no doubt, some apparent exceptions. The Swallow-tail Butterfly, for instance, has red spots and still is smooth; but as it emits a strongly-scented liquid when alarmed, it is probably distasteful to birds. I cannot recall any other case of a British caterpillar which has conspicuous red spots or lines, and yet is smooth.

Blue is, among caterpillars, even a rarer color than red. Indeed, among our larger larvae, the only cases I can recall are the Lappets, which have two conspicuous blue bands, the Death's-head Moth, which has broad diagonal bands, and two of the Hawk-moths, which have two bright blue oval patches on the third segment. The Lappets are protected by being hairy, but why they have the blue bands I have no idea. It is interesting, that both the other species frequent plants which have blue flowers. The peculiar hues of the Death's-head caterpillar, which feeds on the potato, unite so beautifully the brown of the earth, the yellow and green of the leaves, and the blue of the flowers, that, in spite of its size, it can scarcely be perceived unless the eye be focussed exactly upon it.

The Oleander Hawk-moth is also an interesting case. Many of the Hawk-moth caterpillars have eye-like spots, to which I shall have to allude again presently. These are generally reddish or yellowish, but in this species, which feeds on the periwinkle, they are bright blue, and in form as well as color closely resemble the blue petals of that flower. One other species, the Sharp-winged Hawk-moth, also has two smaller blue spots, with reference to which I can make no suggestion. It is a very rare species, and I have never seen it. Possibly, in this case, the blue spots may be an inherited character, and have no reference to the present habits. They are, at any rate, quite small.

No one who looks at any representations of Hawk-moth caterpillars can fail to be struck by the peculiar coloring of those belonging to the Pine Moth, which differ in style of coloring from all other sphinx larvae, having longitudinal bands of brown and green. Why is this? Their _habitat_ is different. They feed on the leaves of the pinaster, and their peculiar coloring offers a general similarity to the brown twigs and narrow green leaves of a conifer. There are not many species of butterflies or moths which feed on the pine, but there are a few: and most, if not all of them, have a very analogous style of coloring to that of the Pine Moth, while the latter has also tufts of bluish-green hair which singularly mimic the leaves of the pine. It is still more remarkable that in a different order of insects we again find species--for instance one of the saw-flies--which live on the pine, and in which the same style of coloring is repeated.

Let us now take a single group, and see how far we can explain its various colors and markings, and what are the lessons which they teach us. For this purpose, I think I cannot do better than select the larvae of the Hawk-moths, which have just been the subject of a masterly work by Dr. Weissmann, from which most of the following facts are taken.

The caterpillars of this group are very different in color--green, white, yellow, brown, sometimes even gaudy, varied with spots, patches, streaks, and lines. Now, are these differences merely casual and accidental, or have they a meaning and a purpose? In many, perhaps in most cases, the markings serve for the purpose of concealment. When, indeed, we see caterpillars represented on a white sheet of paper, or if we put them on a plain table, and focus the eye on them, the colors and markings would seem, if possible, to render them even more conspicuous; but amongst the intricate lines and varied colors of foliage and flowers, and if the insect be a little out of focus, the effect is very different.

Let us begin with the Elephant Hawk-moth. The caterpillars (Fig. 3), as represented in most entomological works, are of two varieties, most of them brown, but some green. Both have a white line on the three first segments; two remarkable eye-like spots on the fourth and fifth, and a very faint median line; and are rather more than four inches long. I will direct your attention specially, for the moment, to three points:--What do the eye-spots and the faint lateral line mean? and why are some green and some brown, offering thus such a marked contrast to the leaves of the small epilobe on which they feed? Other questions will suggest themselves later. I must now call your attention to the fact, that when the caterpillars first quit the egg, and come into the world (Fig. 4), they are quite different in appearance, being, like so many other small caterpillars, bright green, and almost exactly the color of the leaves on which they feed. That this color is not the necessary or direct consequence of the food, we see from the case of quadrupeds, which, as I need scarcely say, are never green. It is, however, so obviously a protection to small caterpillars, that this explanation of their green color suggests itself to every one.

After five or six days, and when they are about a quarter of an inch in length, they go through their first moult. In their second stage (Fig. 5), they have two white lines, stretching along the body from the horn to the head; and after a few days (Fig. 6), but not at first, traces of the eye-spots appear on the fourth and fifth segments, shown by a slight wave in the upper line. After another five or six days, and when about half an inch in length, our caterpillars moult again. In their third stage (Fig. 7), the commencement of the eye-spots is more marked, while, on the contrary, the lower longitudinal line has disappeared. After another moult (Fig. 8), the eye-spots are still more distinct, the white gradually becomes surrounded by a black line, while in the next stage (Fig. 9) the centre becomes somewhat violet. The white lines have almost or entirely disappeared, and in some specimens faint diagonal lines make their appearance. Some few assume a brownish tint, but not many. A fourth moult takes place in seven or eight days, and when the caterpillars are about an inch and a half in length. Now, the difference shows itself still more between the two varieties, some remaining green, while the majority become brown. The eye-spots are more marked, and the pupil more distinct, the diagonal lines plainer, while the white line is only indicated on the first three, and on the eleventh segment. The last stage (Fig. 9) has been already described.

Now, the principal points to which I wish to draw attention are (1) the green color, (2) the longitudinal lines, (3) the diagonal lines, (4) the brown color, and (5) the eye-spots.

As regards the first three, however, I think I need say no more. The value of the green color to the young larva is obvious; nor is it much less clear that when the insect is somewhat larger, the longitudinal lines are a great advantage, while subsequently diagonal ones become even more important.

The next point is the color of the mature caterpillars. We have seen that some are green, and others brown. The green ones are obviously merely those which have retained their original color. Now for the brown color. This probably makes the caterpillar even more conspicuous among the green leaves than would otherwise be the case. Let us see, then, whether the habits of the insect will throw any light upon the riddle. What would you do if you were a big caterpillar? Why, like most other defenceless creatures, you would feed by night, and lie concealed by day. So do these caterpillars. When the morning light comes, they creep down the stem of the food plant, and lie concealed among the thick herbage, and dry sticks and leaves, near the ground; and it is obvious that under such circumstances the brown color really becomes a protection. It might indeed be argued that the caterpillars, having become brown, concealed themselves on the ground; and that we were, in fact, reversing the state of things. But this is not so; because, while we may say, as a general rule, that (with some exceptions due to obvious causes) large caterpillars feed by night and lie concealed by day, it is by no means always the case that they are brown; some of them still retaining the green color. We may then conclude that the habit of concealing themselves by day came first, and that the brown color is a later adaptation. It is, moreover, interesting to note that while the caterpillars which live on low plants often go down to the ground and turn brown, those which feed on large trees or plants remain on the under side of the leaves, and retain their green color.

Thus, in the Eyed Hawk-moth, which feeds on the willow and sallow; the Poplar Hawk-moth, which feeds on the poplar; and the Lime Hawk-moth, which frequents the lime, the caterpillars all remain green; while in those which frequent low plants, such as the Convolvulus Hawk-moth, which frequents the convolvulus; the Oleander Hawk-moth, which feeds in this country on the periwinkle; and other species, most of the caterpillars turn brown. There are, indeed, some caterpillars which are brown, and still do not go down to the ground--as, for instance, those of the Geometridae generally. These caterpillars, however, as already mentioned, place themselves in peculiar attitudes, which, combined with their brown color, make them look almost exactly like bits of stick or dead twigs.

The last of the five points to which I called your attention was the eye-spots. In some cases, spots may serve for concealment, by resembling the marks on dead leaves. In one species, which feeds on the hippophae, or sea buckthorn, a gray-green plant, the caterpillar also is a similar gray-green, and has, when full grown, a single red spot on each side--which, as Weissmann suggests, at first sight much resembles in color and size one of the berries of the hippophae. This might, at first, be supposed to constitute a danger, and therefore to be a disadvantage; but the seeds, though present, are not ripe, and consequently are not touched by birds. Again, in another caterpillar, there is an eye-spot on each segment, which mimics the flower of the plant on which it feeds. White spots, in some cases, also resemble the spots of light which penetrate foliage. In other instances, however, and at any rate in our Elephant Hawk-moth, the eye-spots certainly render the insect more conspicuous.

Now in some cases, this is an advantage, rather than a drawback. Suppose that from the nature of its food, from its being covered with hair, or from any other cause, a small green caterpillar were very bitter, or disagreeable or dangerous as food, still, in the number of small green caterpillars which birds love, it would be continually swallowed by mistake. If, on the other hand, it had a conspicuous and peculiar color, its evil taste would serve to protect it, because the birds would soon recognize and avoid it, as has been proved experimentally. I have already alluded to a case of this among the Hawk-moths, in a species which, feeding on euphorbia, with its bitter milky juice, is very distasteful to birds, and is thus actually protected by its bold and striking colors. The spots on our Elephant Hawk-moth caterpillar do not admit of this explanation, because the insect is quite good to eat--I mean, for birds. We must, therefore, if possible, account for these spots in some other way. There can, I think, be little doubt that Weissmann is right when he suggests that the eye-spots actually protect the caterpillar, by frightening its foes.

Every one must have observed that these large caterpillars--as, for instance, that of the small Elephant Hawk-moth (Fig. 10)--have a sort of uncanny poisonous appearance; that they suggest a small thick snake or other evil beast, and the so-called "eyes" do much to increase the deception. Moreover, the segment on which they are placed is swollen, and the insect, when in danger, has the habit of retracting its head and front segments, which gives it an additional resemblance to some small reptile. That small birds are, as a matter of fact, afraid of these caterpillars (which, however, I need not say, are in reality altogether harmless), Weissmann has proved by actual experiment. He put one of these caterpillars in a tray in which he was accustomed to place seed for birds. Soon a little flock of sparrows and other small birds assembled to feed as usual. One of them lit on the edge of this tray, and was just going to hop in, when she spied the caterpillar. Immediately she began bobbing her head up and down, but was afraid to go nearer. Another joined her, and then another, until at last there was a little company of ten or twelve birds, all looking on in astonishment, but not one ventured into the tray; while one bird, which lit in it unsuspectingly, beat a hasty retreat in evident alarm, as soon as she perceived the caterpillar. After watching for some time, Weissmann removed it, when the birds soon attacked the seeds. Other caterpillars also are probably protected by their curious resemblance to spotted snakes.

Moreover, we may learn another very interesting lesson from these caterpillars. They leave the egg, as we have seen, a plain green, like so many other caterpillars, and gradually acquire a succession of markings, the utility of which I have just attempted to explain. The young larva, in fact, represents an old form, and the species, in the lapse of ages, has gone through the stage which each individual now passes through in a few weeks. Thus, the caterpillar of _Chaerocampa porcellus_, a species very nearly allied to the Elephant Hawk-moth, passes through almost exactly the same stages as that species. But it leaves the egg with a subdorsal line, which the caterpillar of the Elephant Hawk-moth does not acquire until after its first moult. No one can doubt, however, that there was a time when the new-born caterpillars of the small Elephant Hawk-moth were plain green, like those of the large one. Again, if we compare the mature caterpillars of this group of Hawk-moths, we shall find there are some forms which never develop eye-spots, but which, even when full grown, correspond to the second stage of the Elephant Hawk-moth. Here, then, we seem to have species still in the stage which the Elephant Hawk-moth must have passed through long ago.

The genus _Deilephila_, of which we have three species--the Euphorbia Hawk-moth, the Galium Hawk-moth, and the Rayed Hawk-moth--is also very instructive. The caterpillar of the Euphorbia Hawk-moth begins life of a clear green color, without a trace of the subsequent markings. After the first moult, however, it has a number of black patches, a white line, and a series of white dots, and has, therefore, at one bound, acquired characters which in the Elephant Hawk-moth, as we have seen, were only very gradually assumed. In the third stage, the line has disappeared, leaving the white spots. In the fourth, the caterpillars have become very variable, but are generally much darker than before, and have a number of white dots under the spots. In the fifth stage, there is a second row of white spots under the first. The caterpillars not being good to eat, there is, as has been already pointed out, no need for, or attempt at, concealment. Now if we compare the mature caterpillars of other species of the genus, we shall find that they represent phases in the development of the Euphorbia Hawk-moth. The Sea Buckthorn Hawk-moth, for instance, even when full grown, is a plain green, with only a trace of the line, and corresponds, therefore, with a very early stage of the Euphorbia Hawk-moth; there is another species found in South Russia, which has the line, and represents the second stage of the Euphorbia Hawk-moth; another has the line and the row of spots, and represents, therefore, the third stage; lastly, there are some which have progressed further, and lost the longitudinal line, but they never acquire the second row of spots which characterizes the last stage of the Euphorbia Hawk-moth.

Thus, then, the individual life of certain caterpillars gives us a clue to the history of the species in past ages.

For such inquiries as this, the larvae of Lepidoptera are particularly suitable, because they live an exposed life; because the different species, even of the same genus, often feed on different plants, and are therefore exposed to different conditions; and last, not least, because we know more about the larvae of the butterflies and moths than about those of any other insects. The larvae of ants all live in the dark; they are fed by the perfect ants, and being therefore all subject to very similar conditions, are all very much alike. It would puzzle even a good naturalist to determine the species of an ant larva, while, as we all know, the caterpillars of butterflies and moths are as easy to distinguish as the perfect insects; they differ from one another as much as, sometimes more than, the butterflies and moths themselves.

There are five principal types of coloring among caterpillars. Those which live inside wood, or leaves, or underground, are generally of a uniform pale hue; the small leaf-eating caterpillars are green, like the leaves on which they feed. The other three types may, to compare small things with great, be likened to the three types of coloring among cats. There are the ground cats, such as the lion or puma, which are brownish or sand color, like the open places they frequent. So also caterpillars which conceal themselves by day at the roots of their food-plant, tend, as we have seen, even if originally green, to assume the color of earth. Nor must I omit to mention the _Geometridae_, to which I have already referred, and which, from their brown color, their peculiar attitudes, and the frequent presence of warts or protuberances, closely mimic bits of dry stick. That the caterpillars of these species were originally green, we may infer from the fact that some of them at least are still of that color when first born.

Then there are the spotted or eyed cats, such as the leopard, which live among trees; and their peculiar coloring renders them less conspicuous by simulating spots of light which penetrate through foliage. So also many caterpillars are marked with spots, eyes, or patches of color. Lastly, there are the jungle cats, of which the tiger is the typical species, and which have stripes, rendering them very difficult to see among the brown grass which they frequent. It may, perhaps, be said that this comparison fails, because the stripes of tigers are perpendicular, while those of caterpillars are either longitudinal or oblique. This, however, so far from constituting a real difference, confirms the explanation; because in each case the direction of the lines follows that of the foliage. The tiger, walking horizontally on the ground, has transverse bars; the caterpillar, clinging to the grass in a vertical position, has longitudinal lines; while those which live on large-veined leaves have oblique lines, like the oblique ribs of the leaves.

Red and blue are rare colors among caterpillars. Omitting minute dots, we have six species more or less marked with red or orange. Of these, two are spiny, two hairy, and one protected by scent-emitting tentacles. The orange medio-dorsal line of the Bedford Butterfly is not very conspicuous, and has been omitted in some descriptions. Blue is even rarer than red; in fact, none of our butterfly larvae can be said to exhibit this color.

Now let us turn to the moths. I have taken all the larger species, amounting to rather more than one hundred and twenty; out of which sixty-eight are hairy or downy; and of these forty-eight are marked with black or gray, fifteen brown or brownish, two yellowish-green, one bluish-gray, one striped with yellow and black, and one reddish-gray. There are two yellowish-green hairy species, which might be regarded as exceptions: one, that of the Five-spotted Burnet-moth, is marked with black and yellow, and the other is variable in color, some specimens of this caterpillar being orange. This last species is also marked with black, so that neither of these species can be considered of the green color which serves as a protection. Thus, among the larger caterpillars, there is not a single hairy species of the usual green color. On the other hand, there are fifty species with black or blackish caterpillars, and of these forty-eight are hairy or downy.

In ten of our larger moths the caterpillars are more or less marked with red. Of these, three are hairy, one is an internal feeder, four have reddish lines, which probably serve for protection by simulating lines of shadow, and one, the Euphorbia Hawk-moth, is inedible. The last, the striped Hawk-moth, is rare, and I have never seen the caterpillar; but to judge from figures, the reddish line and spots would render it, not more, but less conspicuous amongst the low herbage which it frequents.

Seven species only of the larger moths have any blue; of these, four are hairy, the other three are Hawk-moths. In one, the Death's Head, the violet color of the side stripes certainly renders the insect less conspicuous among the flowers of the potato, on which it feeds. In the Oleander Hawk-moth there are two blue patches, which, both in color and form, curiously resemble the petals of the periwinkle, on which it feeds. In the third species, the small Elephant Hawk-moth, the bluish spots form the centres of the above-mentioned eye-like spots.

In one family, as already mentioned, the caterpillars are very often brown, and closely resemble bits of stick, the similarity being much increased by the peculiar attitudes they assume. On the other hand, the large brown caterpillars of certain Hawk-moths are night feeders, concealing themselves on the ground by day; and it is remarkable that while those species, such as the Convolvulus Hawk-moth, which feed on low plants, turn brown as they increase in age and size, others, which frequent trees, and cannot therefore descend to the ground for concealment, remain green throughout life. Omitting these, there are among the larger species, seventeen which are brown, of which twelve are hairy, and two have extensile caudal filaments. The others closely resemble bits of stick, and place themselves in peculiar and stiff attitudes.

And thus, summing up the caterpillars, both of butterflies and moths, out of eighty-eight spiny and hairy species, only one is green, and even this may not be protectively colored, since it has conspicuous yellow warts. On the other hand, a very great majority of the black and brown caterpillars, as well as those more or less marked with blue and red, are either hairy or spiny, or have some special protection.

Here, then, I think we see reasons, for many at any rate, of the variations of color and markings in caterpillars, which at first sight seem so fantastic and inexplicable. I should, however, produce an impression very different from that which I wish to convey, were I to lead you to suppose that all these varieties have been explained, or are understood. Far from it; they still offer a large field for study; nevertheless, I venture to think the evidence now brought forward, however imperfectly, is at least sufficient to justify the conclusion that there is not a hair or a line, not a spot or a color, for which there is not a reason--which has not a purpose or a meaning in the economy of nature.

PROTECTIVE RESEMBLANCES IN SPIDERS

BY ELIZABETH G. PECKHAM.[10]

[10] Abbreviated from the occasional Papers of the Natural History Society of Wisconsin, Vol. I., 1889. By permission.

There are, among spiders, two forms of protective modification: the first, including all cases of protective resemblance to vegetable and inorganic things--that is, all modifications of color or of color and form that tend to make them inconspicuous in their natural relations--I shall call direct protection. The second form, which I shall call indirect protection, includes two classes, the spiders which are specially protected themselves and those which mimic other creatures which are specially protected.

Spiders are specially protected when they become inedible through the acquisition of hard plates and sharp spines. The modification of form is frequently accompanied by conspicuous colors, which warn their enemies that they belong to an unpalatable class.

The second class of indirectly protected spiders--those that mimic specially protected creatures--presents some difficulties, since it is not always easy to determine whether the purpose of mimicry is protection or the capture of prey. The resemblance may, as is frequently the case in direct protection, serve both purposes.

In looking for instances of protective form and color among spiders we encounter one difficulty at the outset. The meaning of a protective peculiarity can be determined only when the animal is seen in its natural home. The number of strangely modified forms depicted in descriptive works on spiders is enormous. Bodies are twisted, elongated, inflated, flattened, truncated, covered with tubercles or spines, enclosed within chitinous plates, colored like bark, like lichens, like flowers of every imaginable hue, like bird droppings, like sand or stones, and in every one of these modifications there is doubtless an adaptation of the spider to its surroundings which, when it is studied out of its natural relations, we can only guess at.

It has been well said that in these protective resemblances those features of the portrait are most attended to by nature which produce the most effective deception when seen in nature; the faithfulness of the resemblance being much less striking when seen in the cabinet....

DIRECT PROTECTION. RESEMBLANCES TO VEGETABLE AND INORGANIC THINGS.--As a general rule the forms and colors of spiders are adapted to render them inconspicuous in their natural homes. Bright colored spiders, ... either keep hidden away or are found upon flowers whose tints harmonize with their own. This rule, while it has numerous exceptions, is borne out by the great majority of cases. A good illustration is found in the genus Uloborus, of which the members bear a deceptive resemblance to small pieces of bark, or to such bits of rubbish as commonly become entangled in old deserted webs. The only species in our neighborhood is Uloborus plumipes, which I have almost invariably found building in dead branches, where its disguise is more effective than it would be among fresh leaves. The spider is always found in the middle of the web, with its legs extended in a line with the body. There has been, in this species, a development along several lines, resulting in a disguise of considerable complexity. Its form and color make it like a scrap of bark, its body being truncated and diversified with small humps, while its first legs are very uneven, bearing heavy fringes of hair on the tibia and having the terminal joints slender. Its color is a soft wood-brown or gray, mottled with white. It has the habit of hanging motionless in the web for hours at a time, swaying in the wind like an inanimate object. The strands of its web are rough and inelastic, so that they are frequently broken; this gives it the appearance of one of those dilapidated and deserted webs in which bits of wind-blown rubbish are frequently entangled....

Out of seven examples of the species taken during one summer, five were found in dead tamarack branches, one on a dead bush, and the seventh, an interesting variety, under the eaves of a porch. My eye was caught by what seemed to be a string of eleven cocoons (it is not common to see more than four in a web). On attempting to take them down I was surprised to see one of the supposed cocoons begin to shake the web violently. Ten were what they seemed to be, but the eleventh was the mother spider, whose color and general appearance was exactly like that of the little cases that she had made for her eggs....

We come now to a large and interesting class in genus Epeira. I refer to those species, mostly nocturnal, which are protected during the day, not by hiding in crevices, nor in any way actually getting out of sight, but by the close resemblance which they bear to the bark of the trees to which they cling. This resemblance is brought about in two ways; through their color, which is like that of wood or lichens, and through their tuberculated and rugose forms, which resemble rough bark.

One of the most remarkable of these forms is C. mitralis, a Madagascar species, which, looked at in profile, probably resembles a woody knot. The abdomen is divided into two divergent cones (Fig. 1). The entire upper surface of the body is covered with conical elevations, which render it rough and uneven; the sides of the abdomen are made up of several layers, which form stages, one above another, like the ridges of bark on a woody excrescence. The legs, formed of wide, flattened plates, make the base. The color of the spider is yellowish-gray, varied with white and dark reddish-brown. It has the habit of perching on a branch and clasping it like a bird, so that the elaborate modification of form, which would be useless if the spider hung exposed in the web, is made as effective as possible.

To take an example nearer home, E. infumata is a large, round-bodied spider, with two humps on the abdomen, which Emerton describes from New England as being brown, mottled with white and black; he adds that when it draws in its feet it looks like a lump of dirt. Infumata, in Wisconsin, has always a good deal of bluish-green on the upper surface of the abdomen. This may be a variety which has been so developed as to resemble the lichens which cover the tree to which it clings. It is one of the spiders which bear a good deal of handling without uncurling its legs, or showing any sign of life. Its humpy form and its color give it a very inanimate appearance. It is rather common in our neighborhood and may be caught in the late twilight while building its web, but to search for it in the daytime, even among the trees that it most frequents, is an almost hopeless task. A more grotesque form is E. stellata, in which the abdomen has not two, but twelve or fifteen humps. These are so disposed that the edge of the abdomen, all around, is scalloped. The colors are light and dark brown, modified by gray and white hairs. This spider remains motionless during the daytime, keeping its legs drawn up to its body. It is common on grass and low bushes. It is not found in Wisconsin, but the description of it suggests a resemblance to a piece of dead leaf.

There are many other spiders in this genus that have humps and are colored in brown, gray or dull yellow, as nordmanii, angulata, solitaria, etc. It is an almost universal habit among the Epeiridae to drop to the ground when threatened, and when a humped gray or brown spider drops to the ground and draws in its legs it is nearly indistinguishable from the lumps of earth, sticks and stones that surround it.

One of the Therididae which has the same protection is Ulesanis americana (Fig. 3). The abdomen, which covers the cephalothorax nearly to the eyes, has a prominent hump in the middle of the back and four or five others behind. Its color is in shades of brown and yellow.

Analogous to the humped Epeiridae is Thomisus foka, of Madagascar, a spider which is regarded with great terror by the natives, as being so poisonous that even its breath is deadly. They say that cattle, when about to lie down, look carefully about to see if one of these spiders is in the neighborhood. This dread is, no doubt, inspired by the strange and uncanny aspect of a perfectly harmless creature. It has a rugose, tuberculated body of trapezoid form, the colors being brown and reddish, while the whole aspect is crab-like. The thick, short legs are reddish, covered with tubercules. The secret of its strange form is made clear when we learn that it resembles in color and general appearance the fruit of Hymenaea verrucosa, a tree common in the forests where this spider is found.

Among the curious forms which must have been developed through advantageous variations but which we are unable to explain, is Eriauchenus workmanni (Fig. 4).

Epeira prompta, a variety of parvula, is a common spider in the State of Wisconsin. It is most frequently seen on cedar bushes, where its color harmonizes with that of the foliage and fruit. During the day it usually rests on a branch near its web. The back of the abdomen is of a peculiar bluish-green, exactly like that of the lichens growing on tree trunks. The bluish color is broken by waving black lines which imitate the curling edges of the lichens. The one represented in the plate was found on an old cedar which was covered with lichens. It was kept for two weeks in a glass-covered box, where it spent most of the time crouching in a corner. It built no web, but spun some irregular lines to run about on. It ate gnats, flies, and once a little jumping spider, S. pulex, which we were keeping in the same box, leaping upon its prey, as noted by Hentz, like an Attus. This seems a curious habit to be acquired by an Epeirid, since spiders, as we have noticed among our captives, are usually dependent for food upon what is caught in their webs. Prompta moves awkwardly, but very rapidly.

Drapetisca socialis, while quite a different looking spider, is protected in the same way--by its resemblance to the bark upon which it lives. Emerton speaks of finding it on the bark of spruce trees, which it "closely resembles in color." Menge says that it is common in Prussia, where it is seen in great numbers on fir trees, whose spotted bark it resembles in color, so that it is not easily seen. We have found them, most commonly, upon birch trees, and in this situation their color adaptation is perfect. Both the spider and the peeling bark of the tree are of a light silvery brown, covered with little blackish marks. On the bark these marks are, of course, irregular, while on the spider they form a pattern made up of straight and curved lines and dots, the legs being silvery, barred with blackish.

Another little Theridion that is found on birch bark has the same colors arranged a little differently. The abdomen above has a large and peculiarly irregular black patch, which shades off into mottled brown and black on the sides and below. The cephalothorax has stripes of brown and black, and the legs are barred with light and dark brown.

Spiders that live upon walls, fences, tree trunks, or on the ground harmonize in color with the surfaces upon which they are found, being usually gray, brown or yellow, mottled with black and white. This proposition is so well established as to need but few illustrations. The Therididae furnish many examples, as T. murarium, a gray spider varied with black and white, said by Emerton to live usually "under stones and fences, where it is well concealed by its color"; and Lophocarenum rostratum, a yellowish-brown spider, found among leaves on the ground. Among the Attidae bright sexual coloring often gains the ascendancy over the protective tints, yet this family gives us good examples in such species as M. familiaris and S. pulex.

To these may be added an as yet undescribed species which we discovered last season in a neighborhood that we had searched thoroughly for eight summers. We found the new spider in great numbers, but could only detect it by a close scrutiny of the rail fences on which it lived, its color being dark gray....

The last instance that I shall cite is a predaceous spider which is disguised from both its enemies and its prey by an elaborate combination of form, color, position, and character of web. I refer to Ornithoscatoides decipiens (Fig. 5), first described by Forbes and afterwards by Cambridge, the latter author giving in the same paper descriptions of three other species of the same genus, whose habits have not been noted, but whose protection is evidently of the same order as that of decipiens. I give Forbes's interesting account of his capture of decipiens, quoting also the remarks by which Cambridge prefaces his description, since his explanation of the gradual development, through Natural Selection, of the spider's deceptive appearance applies as well to all the cases of protective disguise which have been here enumerated.

The capture is described as follows:--

"On June 25th, 1881, in the forest near the village of Lampar, on the banks of the Moesi river in Sumatra, while my 'boys' were procuring for me some botanical specimens from a high tree, I was rather dreamily looking on the shrubs before me, when I became conscious of my eyes resting on a bird-excreta-marked leaf. How strange, I thought, it is that I have never got another specimen of that curious spider I found in Java which simulated a patch just like this! I plucked the leaf by the petiole while so cogitating, and looked at it half listlessly for some moments, mentally remarking how closely that other spider had copied nature, when, to my delighted surprise, I discovered that I had actually secured a second specimen, but the imitation was so exquisite that I really did not perceive how matters stood for some moments. The spider never moved while I was plucking or twirling the leaf, and it was only when I placed the tip of my little finger on it, that I observed that it was a spider, when it, without any displacement of itself, flashed its falces into my flesh.

"The first specimen I got was in W. Java, while hunting one day for Lepidoptera. I observed a specimen of one of the Hesperidae sitting, as is often a custom of theirs, on the excreta of a bird on a leaf; I crept near it, intending to examine what they find in what one is inclined to consider incongruous food for a butterfly. I approached nearer and nearer, and at last caught it between my fingers, when I found that it had as I thought become glued by its feet to the mass; but on pulling gently the spider, to my amazement, disclosed itself by letting go its hold: only then did I discover that I was not looking on a veritable bird's excreta.... The spider is in general color white, spotted here and there with black; on the underside its rather irregularly shaped and prominent abdomen is almost all white, of a pure chalk white; the angles of the legs are, however, shining jet-black. The spider does not make an ordinary web, but only the thinnest film on the surface of the leaf. The appearance of the excreta rather recently left by a bird on a leaf is well known. There is a pure white deposit in the centre, thinning out round the margin, while in the central mass are dark portions variously disposed; as the leaf is rarely horizontal, the more liquid portions run for some distance. Now, this spider one might almost imagine to have in its rambles 'marked and inwardly discerned' what it had observed, and to have set about practising the 'wrinkles' gained; for it first weaves a small, irregular patch of white web on some prominent leaf, then a narrow streak laid down towards its sloping margin ending in a small knob; it then takes its place on the centre of the irregular spot on its back, crosses its black-angled legs over its thorax, and waits. Its pure white abdomen represents the central mass of the bird's excreta, the black legs the dark portions of the slime, while the web above described which it has spun represents the more watery marginal part (become dry), even to the run-off portion with the thickened knob (which was not accidental, as it occurred in both cases), like the residue which semi-fluid substances ending in a drop leave on evaporation. It keeps itself in position on its back by thrusting under the web below it the spines with which the anterior upper surfaces of the legs are furnished." ...

PROTECTIVE HABITS.--Going along with these forms of protective resemblance, we find certain habits which sometimes serve independently to protect the spider, but oftener are supplemental to color and form. Many species hide in crevices or in leaves which they roll up and bind together at the edges. In the Epeiridae some are like thaddeus, which makes a little tent of silk under a leaf near its web. The young thaddeus also makes a tent, but spins its little geometrical web on the under side of the leaf, the edges being bent downward. E. insularis has the more common habit of forming its tent by drawing the edges of two or three leaves together with strands of web; in this it sits all day, but at night descends and occupies the centre of the web during the hours of darkness. I have often found it in this position when hunting nocturnal species by lantern light. It is probable that in tropical countries the monkeys, and perhaps the birds, which devour these large Epeiridae have learned to recognize their webs, which are very large and conspicuous, and to trace them to their hiding places close by; and thus may have arisen the curious habit noticed by Vinson as possessed by E. nocturna and E. Isabella of destroying the web each morning and rebuilding it at night; the spider in this way gaining greater security from diurnal enemies.

Atypus abbotii builds a purse-shaped tube which is found attached to the bark of trees, and which has the external surface dark and covered with sand. The trap-doors which close the nest of some of the Territelariae are wonderful examples of protective industry. They fit with such absolute accuracy into the openings of the nests and are so covered on the upper side with moss, earth, lichens, etc., as to be indistinguishable from the surrounding surface.

The rectilinear lines which are stretched in front of the webs of many Epeirids are useful in taking and sending on to the spider the shock which tells of an approaching enemy. Some spiders, when danger threatens, shake the web so violently as to grow indistinct to the eye, and others, as Pholcus atlanticus, hang by the legs and whirl the body rapidly with the same bewildering result....

A habit common to many spiders, especially among the Epeiridae, is that of dropping to the ground at the approach of danger and resting motionless among the dirt, sticks, leaves, etc., which they resemble in color. The holding of the body in some peculiar position, as in Uloborus, Hyptioides, and the flower-like Thomisidae, is a necessary accompaniment to the color modification.

The cocoons of spiders are seldom left exposed and unprotected. We find them in corners and crevices, concealed in rolled up leaves or under bark. Very often the cocoon itself is covered over with a sheet of web. In some families the mother carries it about with her attached to the underside of the abdomen. In other she carries it in her falces until the young are hatched. The cocoons of others, as Uloborus, Argyrodes, etc., while hung out in the web are still concealed by deceptive form and color, or by being covered with rubbish.

Cambridge speaks of A. brunnea, whose cocoons "are covered over very soon after they are made and the eggs deposited in them, with a coating of clay, which effectually destroys all their form and beauty. This coating of clay answers probably two ends: first, the concealment of the cocoon and its protection from insect enemies; and, secondly, the protection of the eggs from the too powerful rays of the sun, dry clay being (as is well known) one of the best non-conductors of heat."

The peculiar cocoon of C. bisaccata is described by Emerton as follows: "Only one specimen of this (_bisaccata_) was found on a beech tree at New Haven with two cocoons. These were dark brown, as dark as the bark of the tree and as hard. Around the middle of each was a circle of irregular points. One of the cocoons was attached by a strong stem to the bark, and the other was attached in a similar way to the first cocoon. The spider held on to one of the cocoons." In this instance the egg has evidently the same protection as that possessed by the gray, bark-haunting spiders, with the added advantage of hardness.

The habit of distributing the eggs through a number of cocoons made at intervals of several days, is protective. In this way, although one or two of the cocoons may be pierced by the ichneumon, there is a chance that part of the brood may survive.

INDIRECT PROTECTION.--The indirectly protected group includes those spiders which are rendered inedible by the possession of sharp spines and chitinous plates, and also those that mimic other specially protected creatures.

The females of the specially protected group are characterized by the following attributes:

Their inedibility, which they owe to a more or less coriaceous epidermis and an armature of strong sharp spines (Fig. 6).

Their brilliant colors--glistening black and white, yellow, fiery gold, metallic silver, rose-color, blue, orange and blood-red.

Their habit of hanging always exposed in the centre of the web.

In an interesting discussion of the protective value of color and marking in insects, Poulton says that "the smaller convergent groups of nauseous insects often present us with ideally perfect types of warning patterns and colors--simple, crude, strongly contrasted--everything subordinated to the paramount necessity of becoming conspicuous," the memory of enemies being thus strongly appealed to.

This proposition is well illustrated by the Gasteracanthidae. Among larvae the warning colors are almost invariably black and white, or black (or some very dark color), in contrast with yellow, orange and red. These are the colors that also constantly recur among the Gasteracanthidae.

Cases that may be more justly considered exceptions to the rule that these hard, uneatable spiders are conspicuous are such species as Acrosoma rugosa (Fig. 7). One of this species was sent me by Mrs. Treat last summer. It lived for several weeks in my window, making no regular web, but hanging among a few irregular strands. It ate nothing, although provided with insects, but drank greedily of water. It might seem that its black and white coloring would make it conspicuous, but in connection with its irregular shape and its way of hanging motionless in the web it had the opposite effect.

We have no reason to suppose that the class represented in rugosa is like that touched upon by Poulton, in which very protectively colored larvae suddenly assume a terrifying aspect on the near approach of an enemy; still they do enjoy a kind of double protection.

They are inconspicuous, and thus likely to escape attack, but in case they are attacked they have still the advantage of being quickly rejected. This experience cannot be as fatal to them as to the soft and thin skinned larvae. Their hard covering and projecting spines would protect them to such an extent as to give them a fair chance of surviving.

In one respect the inconspicuous Gasteracanthidae have a decided advantage over their bright-colored relatives. The birds, indeed, avoid the conspicuous ones, but their brilliancy serves to attract another enemy against which spines are no protection--the hunter wasp, which, as we have seen in the work of Bates, sometimes provisions its nest wholly with spiders of this family. Mr. Smith gives like testimony, saying:

"Spines on the abdomen of certain spiders would serve as a protection against vertebrate enemies, though they do not protect against the hunter wasps, which frequently provision their nests with these species." He adds, however, that most of the spiny spiders are common, and that their colors make them conspicuous; just as butterflies that are protected by an odor are common and bright-colored....

MIMICRY.--Mimicry, or the imitation of animal forms, while it is a form of indirect protection, differs in no essential respect from the imitation of vegetable and inorganic things. As Bates has said, the object of mimetic tendencies is disguise, and they will work in any direction that answers this purpose.

In nearly all respects spiders come under the three laws given by Wallace, as governing the development of mimetic resemblances in several large classes. These laws are as follows:

1. In an overwhelming majority of cases of mimicry, the animals (or the groups) which resemble each other inhabit the same country, the same district, and in most cases are to be found together on the very same spot.

2. These resemblances are not indiscriminate, but are limited to certain groups, which, in every case, are abundant in species and individuals, and can often be ascertained to have some special protection.

3. The species which resemble or "mimic" these dominant groups, are comparatively less abundant in individuals, and are often very rare.

The second and third of these laws are confirmed by what we know of mimetic resemblances among spiders. They mimic ants much oftener than other creatures, and ants are very abundant, are specially protected, and are much more numerous than the mimetic spiders. To the first law, also, they conform to a great extent, since everything tends to show that in tropical America and in Africa the ant and the spider, the one mimicked and the other mimicking, are always found together. So far as I can discover, however, the ant-like spiders of North America are not found in company with any species of ant which they resemble. This may be because they do not mimic any particular species, but only the general ant-like form; or, considering that the genera which contain their nearest relatives are much more abundant in Central and South America, it may be that these forms were originally tropical, mimicking some tropical species of ants, and that after the Glacial Epoch they migrated northward, leaving the ants behind them. However this may be, their peculiar form has served them well, since they have maintained themselves as fairly abundant species with a lower fecundity than is found in any other group of spiders.

The cases in which one species mimics another may be divided, according to the kind of benefit derived, into four classes: Class 1. As a rule, where we find one species mimicking another, the mimicked species possesses some special means of defence against the enemies of both. This defence may consist of a disagreeable taste or odor, as in the Heliconidae, which are mimicked by other butterflies; of some special weapon of offence, as where wasps and bees are mimicked by flies and moths, or poisonous vipers by harmless caterpillars; or of a hard shell, as where the coriaceous beetles are mimicked by those that are soft-bodied.

Instances of this rule are exceedingly numerous; indeed, Wallace says that specially protected forms are always mimicked; still we have nothing mimicking our Gasteracanthidae.

Class 2. The mimetic may prey upon the mimicked species, its disguise enabling it to gain a near approach to its victims; as the mantis, mentioned by Bates as exactly resembling the white ants upon which it feeds; and the flies which mimic bees, upon which they are parasitic, and are thus able to enter the nests of the bees and lay eggs on the larvae.

Class 3. The mimetic species may, by its imitation, be protected from the attacks of the creature it mimics, as is the case with the crickets and grasshoppers which mimic their deadly foe, the hunter wasp.

Class 4. The mimetic species may prey upon some creature which is found commonly with, and is not eaten by, the mimicked species.

No two of these classes are mutually destructive so that in any case of mimicry a double advantage may be gained.

Let us see which of these advantages has directed the development of mimetic tendencies among spiders.

While among beetles and butterflies we most commonly find mimicry of one species by another within the same order, we have no instance of a spider mimicking another spider. This may be accounted for by the fact that the specially protected spiders depend for their safety upon the possession of hard plates and spinous processes, and although the hardened epidermis might be imitated (we know that hard-shelled beetles are mimicked by others that are soft), spines could scarcely be imitated by a soft-bodied creature with sufficient accuracy to insure disguise.

While spiders most commonly mimic ants, we hear also of their imitating beetles, snail-shells, ichneumons and horseflies. There is also a curious Madagascar species which looks exactly like a little scorpion, the resemblance being heightened by its habit of curving its flexible tail up over its back when irritated.

Those that resemble beetles comprise nearly all the species of the genera Coccorchestes and Homalattus. These are small spiders with short, convex bodies. The abdomen fits closely over the cephalothorax, and the epidermis, which has usually a metallic lustre, is sometimes coriaceous. Striking examples are found in H. coccinelloides, which bears a strong resemblance to beetles of the family Coccinelloidae, and in C. cupreus, in which certain marks on the abdomen imitate the elytra of beetles.

The following account of a spider which mimics a snail-shell is given by Mr. G. F. Atkinson;--

"An undescribed species of _Cyrtarachne_ mimics a snail-shell, the inhabitant of which, during the summer and fall, is very abundant on the leaves of plants in this place. In the species of Cyrtarachne the abdomen partly covers the cephalothorax, is very broad at the base, in this species broader than the length of the spider, and rounds off at the apex. When it rests upon the under side of a leaf with its legs retracted it strongly resembles one of these snail-shells by the color and shape of its abdomen. The two specimens which I collected deceived me at first, but a few threads of silk led me to make the examination. The spider seemed so confident of its protection that it would not move when I jarred the plant, striking it several hard blows. I pulled the spider forcibly from the leaf, and it did not exhibit any signs of movement until transferred to the cyanide bottle." ...

Trimen gives an account of the imitation, by spiders, of horseflies, a case falling into Class 2, as follows:--

"Hunting spiders are in some cases very like their prey, as may everywhere be noticed in the case of the species of Salticus which catch horseflies on sunny walls and fences. The likeness is not in itself more than a general one of size, form and coloring; but its effect is greatly aided by the actions of the spider, which walks hurriedly for short distances, stopping abruptly, and rapidly moving its falces, in evident mimicry of the well-known movements so characteristic of flies."

Instances of spiders mimicking ants are very numerous, and in many cases the resemblance is so close as to, at first sight, deceive a trained naturalist. This resemblance is brought about by the spider's body being elongated and strongly constricted, so that it appears to be composed of three segments instead of two, by the color, by the way in which the spider moves about, zig-zagging from side to side like an ant, and by its habit of holding up one pair of its legs and moving them in such a way that they look exactly like the antennae of an ant.

Ants may be regarded as specially protected, by their sharp, acid flavor, and in some species by the possession of stings or of horny processes.

On the ground that there are birds which do eat ants, and eat them greedily, it has been thought by some naturalists that they cannot be considered specially protected creatures, and that, as spiders can therefore derive no protection from mimicking them, all cases of such mimicry depend upon the spider's increased ability to capture the ants as prey, but I am convinced that this is too hasty a conclusion. It is unquestionably true that some birds feed almost exclusively upon ants, but these are the exceptions. It is a common thing to find that specially protected groups, which are safe from the attacks of most creatures, have their special enemies. Thus, even the nauseous Heliconidae are preyed upon by certain spiders and wasps; and bees, in spite of their stings, are preferred to other insects by the bee-eaters. Moreover, the ant-devouring birds are found largely among the wood-peckers, which eat the ants that run on the trunks of trees, and are therefore not a source of danger to the ant-like spiders, the American species of which, so far as I can learn, live entirely upon the ground.

In the United States comparatively small numbers of either ants or spiders are eaten by birds, but in tropical America there are enormous numbers of humming-birds feeding almost exclusively upon spiders, and there the protective advantage of looking like ants must be of great importance to the smaller species.

Belt considers that the advantages gained by ant-mimicking Central American spiders lies entirely on the side of protection. In relation to this subject he says: "Ant-like spiders have been noticed throughout tropical America and also in Africa. The use that the deceptive resemblance is to them has been explained to be the facility it affords them for approaching ants on which they prey. I am convinced that this explanation is incorrect, so far as the Central American species are concerned. Ants, and especially the stinging species are, so far as my experience goes, not preyed upon by any other insects. No disguise need be adopted to approach them, as they are so bold that they are more likely to attack a spider than a spider them. Neither have they wings to escape by flying, and generally go in large bodies easily found and approached. The use is, I doubt not, the protection the disguise affords against small insectivorous birds. I have found the crops of some humming-birds full of small, soft-bodied spiders, and many other birds feed on them. Stinging-ants, like bees and wasps, are closely resembled by a host of other insects; indeed, whenever I found any insect provided with special means of defence I looked for imitative forms, and was never disappointed in finding them."

The ant-like species are probably protected by their appearance from the attacks of many of the larger spiders. We have kept great numbers of Attidae in captivity, and, although they devoured flies, gnats, larvae, and other spiders, they would never touch ants. Among spiders, however, as among birds, we find that certain groups subsist almost entirely upon ants.

The class of spiders whose mimicry protects them from their enemies, whether they are birds or other spiders, probably includes at least two of our own ant-like species, Synageles picata and Synemosyna formica, which, in confinement, are always hungry for gnats, but will not touch ants, even of small size.

The existence of a class of spiders which mimic the particular species of ants upon which they prey is not to be questioned, but it is doubtful whether the benefit to the spider is increased facility in capturing the ant, or whether it is merely protective. It may be that the spider, by virtue of its resemblance to the ant, not only gets an abundant supply of food, but also escapes being eaten itself, and thus enjoys a double advantage. Both Bates and Wallace take the ground that the advantage derived by the spider consists in greater ease in the capture of prey, but both of these writers refer to spiders only incidentally to illustrate a general proposition, without special consideration of their peculiar conditions.

Mr. Herbert Smith, who has paid a good deal of attention to this subject, is inclined to believe that the mimicry in question is entirely protective. He writes as follows:--

"In the United States there are a few rare spiders that mimic ants. Here at Taperinha we find a good score of species of these spiders aping the various kinds of ants very closely; even the odd, spiny wood-ant, _cryptocerus_, furnishes a pattern, and there are spiders that mimic the wingless ichneumons. We find, after a while, that the spiders prey upon ants just as our spiders catch flies; indeed, this fact has already been noted by other observers. But we go a step beyond the books when we discover not only that the spiders eat the ants, but that they eat the particular ants which they mimic. At all events, we verify this fact in a great number of cases, and we never find the spiders eating any but the mimicked species.... I do not like to hazard a theory on this case of mimicry. It is difficult to suppose that the quick-witted ants would be deceived even by so close a resemblance; and, in any case, it would seem that the spiders do not require such a disguise in order to capture slow-moving ants. Most birds will not eat ants; it seems likely, therefore, that this is simply another example of protection; the spider deceives its enemies, not its prey; it mimics the particular species that it feeds on, because it is seen in that company when it is hunting, and among a host of similar forms is likely to pass unnoticed."

At first sight, and especially in view of the fact that such cases are not uncommon among insects, it would be naturally supposed that the object of the mimicry was to enable the spider to approach its victim without exciting suspicion; and it is difficult to account, on any other supposition, for the very close resemblance between certain species of spiders and the particular species of ants which they prey upon. It seems as though the highest point of _protective_ benefit would have been reached long before the resemblance of the spider to the ant had become so close as it really is. On the other hand, it is difficult to believe that ants are deceived, even by those spiders which mimic them most closely, when we remember that their perceptions are so keen that they discriminate not only between ants of their own and different species, but even between ants of their own species living in two different communities.

The mimicry of ichneumon flies by spiders was noted some years ago by Mr. Herbert Smith. This case comes under Class 3, in which one species mimics another which preys upon it. Great destruction is caused by ichneumons which lay their eggs on the bodies of the live spiders, and the disguise probably protects the spider by leading the fly to mistake it for one of its own species.

We have no proof that spiders ever mimic ants as a method of escaping from them, but it is possible that this sometimes happens. We know that some ants prey upon them. The foraging ants of South America destroy spiders as well as many kinds of insects, and Wallace mentions a small, wood-boring ant which fills its nest with small spiders.

If the spiders that feed upon ants deceive them by their mimicry those which are preyed upon by ants would gain an advantage by a similar disguise. I once placed a little ant-like spider of the genus Herpyllus in a bottle with three ants no larger than itself, which I had caught with it in the sweep-net. In a very few minutes the ants had killed and begun to devour the spider. It may be that the resemblance was sufficiently close to deceive them in the open, but failed when spider and ants were confined together in close quarters.

THE BATH OF THE BIRDS

BY RICHARD JEFFERIES.

One morning Sir Bevis went down to the brook. Standing on the brink, he said: "Brook, Brook! what are you singing? You promised to tell me what you were saying."

The brook did not answer, but went on singing. Bevis listened a minute, and then he picked a willow leaf and threw it into the bubbles and watched it go whirling round and round in the eddies and back up under the fall, where it dived down and presently came up again, and the stream took it and carried it away past the flags. "Brook, Brook!" said Bevis, stamping his foot; "tell me what you are singing."

And the brook, having now finished that part of his song, said: "Bevis, dear; sit down in the shadow of the willow, for it is very hot to-day, and the reapers are at work; sit down under the willow and I will tell you as much as I can remember."

"But the reed said you could not remember anything," said Bevis, leaning back against the willow.

"The reed did not tell you the truth, dear; indeed, he does not know all; the fact is, the reeds are so fond of talking that I scarcely ever answer them now or they would keep on all day long, and I should never hear the sound of my own voice, which I like best. So I do not encourage them, and that is why the reeds think I do not recollect."

"And what is that you sing about?" said Bevis impatiently.

"My darling," said the brook, "I do not know myself always what I am singing about. I am so happy I sing, sing, and never think about what it means; it does not matter what you mean as long as you sing. Sometimes I sing about the sun, who loves me dearly, and tries all day to get at me through the leaves and the green flags that hide me; he sparkles on me everywhere he can, and does not like me to be in the shadow. Sometimes I sing to the wind, who loves me next most dearly, and will come to me everywhere in places where the sun cannot get. He plays with me whenever he can, and strokes me softly and tells me the things he has heard in the woods and on the hills, and sends down the leaves to float along; for he knows I like something to carry. Fling me in some leaves, Bevis, dear.

"Sometimes I sing to the earth and the grass; they are fond of me, too, and listen the best of all. I sing loudest at night to the stars; for they are so far away they would not otherwise hear me."

"But what do you say?" said Bevis; but the brook was too occupied now to heed him and went on.

"Sometimes I sing to the trees; they, too, are fond of me and come as near as they can; they would all come down close to me if they could. They love me like the rest, because I am so happy and never cease my chanting. If I am broken to pieces against a stone, I do not mind in the least; I laugh just the same and even louder. When I come over the hatch, I dash myself to fragments; and sometimes a rainbow comes and stays a little while with me. The trees drink me, and the grass drinks me; the birds come down and drink me; they splash me and are happy. The fishes swim about, and some of them hide in deep corners. Round the bend I go; and the osiers say they never have enough of me. The long grass waves and welcomes me; the moor-hens float with me; the kingfisher is always with me somewhere, and sits on the bough to see his ruddy breast in the water. And you come too, Bevis, now and then to listen to me; and it is all because I am so happy."

"Why are you so happy?" said Bevis.

"I do not know," said the brook. "Perhaps it is because all I think of is this minute; I do not know anything about the minute just gone by, and I do not care one bit about the minute that is just coming; all I care about is this minute, this very minute now. Fling me in some more leaves, Bevis. Why do you go about asking questions, dear? Why don't you sing and do nothing else?"

"Oh, but I want to know all about everything," said Bevis. "Where did you come from, and where are you going, and why don't you go on and let the ground be dry--why don't you run on, and run all away? why are you always here?"

The brook laughed and said: "My dear, I do not know where I came from, and I do not care at all where I am going. What does it matter, my love? All I know is I shall come back again; yes, I shall come back again." The brook sang very low and rather sadly now: "I shall go into the sea and shall be lost; and even you would not know me; ask your father, love; he has sailed over the sea in ships that come to Southampton, and I was close to him, but he did not know me. But by and by, when I am in the sea, the sun will lift me up, and the clouds will float along--look towards the hills, Bevis, dear, every morning and you will see the clouds coming and bringing me with them; and the rain and the dew, and sometimes the thunder and the lightning, will put me down again; and I shall run along here and sing to you, my sweet, if you will come and listen. Fling in some little twigs, my dear, and some bits of bark from the tree."

"That I will," said Bevis; and he picked up a stone and flung it into the water with such a splash that the kingfisher flew away; but the brook only laughed and told him to throw another and to make haste and grow bigger and jump over him.

"S--s, we shall meet by the drinking place," said the grasshopper; and was just hopping off, when Bevis asked him what the birds went down to bathe for.

"I'm sure I do not know," said the grasshopper, speaking fast, for he was rather in a hurry to be gone; he never could stand still long together. "All I can tell you is, that on Midsummer Day every one of the birds has to go down to the brook and walk in and bathe; and it has been the law for so many, many years that no one can remember when it began. They like it very much, because they can show off their fine feathers which are just now in full color; and if you like to go with me, you will be sure to enjoy it."

"So I will," said Bevis; and he followed the grasshopper, who hopped so far at every step that he had to walk fast to keep up with him.

They went on in silence a good way, except that the grasshopper cried "S--s" to his friends in the grass as he passed, and said good-morning also to a mole, who peeped out for a moment.

"Why don't you hop straight?" said Bevis presently. "It seems to me that you hop first one side and then the other, and go in such a zigzag fashion it will take us hours to reach the brook."

"How very stupid you are!" said the grasshopper. "If you go straight, of course you can only see just what is under your feet; but if you go first this way and then that, then you see everything. You are nearly as silly as the ants, who never see anything beautiful all their lives. Be sure you have nothing to do with the ants, Bevis; they are a mean, wretched, miserly set, quite contemptible and beneath notice. Now, I go everywhere, all round the field, and spend my time searching for lovely things; sometimes I find flowers, and sometimes the butterflies come down into the grass and tell me the news; and I am so fond of the sunshine, I sing to it all day long. Tell me, now, is there anything so beautiful as the sunshine and the blue sky, and the green grass, and the velvet and blue and spotted butterflies, and the trees which cast such a pleasant shadow and talk so sweetly, and the brook which is always running? I should like to listen to it for a thousand years."

"I like you," said Bevis; "jump into my hand and I will carry you." He held his hand out flat, and in a second up sprang the grasshopper and alighted on his palm and told him the way to go, and thus they went together merrily.

"Bevis, dear, I do not sing at night; but I always go where I can see a star. I slept under a mushroom last night, and he told me he was pushing up as fast as he could before some one came and picked him to put on a gridiron. I do not lay up any store, because I know I shall die when the summer ends; and what is the use of wealth then? My store and my wealth is the sunshine, dear, and the blue sky, and the green grass, and the delicious brook who never ceases sing, sing, singing all day and night. And all the things are fond of me; the grass and the flowers, and the birds and the animals--all of them love me."

"I think I shall take you home and put you under a glass case on the mantelpiece," said Bevis.

Off jumped the grasshopper in a moment, and fell so lightly on the grass it did not hurt him in the least, though it was as far as if Bevis had tumbled down out of the clouds. Bevis tried to catch him, but he jumped so nimbly this way and that, and hopped to and fro, and lay down in the grass, that his green coat could not be seen. Bevis now went down to the brook and stood on the bank, where it was high, near a bush at the side of the drinking place. "Ah, dear little Sir Bevis!" whispered a reed, bending towards him as the wind blew, "please do not come any nearer; the bank is steep and treacherous, and hollow underneath where the water-rats run. So do not lean over after the forget-me-nots--they are too far for you. Sit down where you are, behind that little bush, and I will tell you all about the bathing. The birds come down to bathe every Midsummer Day, and the goldfinches, and the sparrows, and the blackbirds, and the thrushes, and the swallows, and the wrens, and the robins, and almost every one of them, except two or three, whose great-grandfathers got into disgrace a long while ago. The rooks do not come because they are thieves, and steal the mussels, nor the crows, who are a very bad lot; the swan does not come either, unless the brook is muddy after a storm. The swan is so tired of seeing himself in the water that he quite hates it, and that is the reason he holds his neck so high, that he may not see more of himself than he can help."

Soon the birds came. They were all in their very best and brightest feathers, and as the sun shone on them and they splashed the water and strutted about, Bevis thought he had never seen anything so beautiful.

They did not all bathe, for some of them were specially permitted only to drink instead, but they all came, and all in their newest dresses. So bright was the goldfinch's wing, that the lark, though she did not dare speak, had no doubt she rouged. The sparrow, brushed and neat, so quiet and subdued in his brown velvet, looked quite aristocratic among so much flaunting color. As for the blackbird he had carefully washed himself in the spring before he came to bathe in the brook, and he glanced round with a bold and defiant air, as much as to say: "There is not one of you who has so yellow a bill, and so beautiful a black coat as I have." In the bush the bullfinch, who did not care much to mix with the crowd, moved restlessly to and fro. The robin looked all the time at Bevis, so anxious was he for admiration. The wood-pigeon, very consequential, affected not to see the dove, whom Bevis longed to stroke, but could not, as he had promised the reed to keep still.

Bevis looked up into the sky, and there was the hawk, almost up among the white clouds, soaring round and round, and watching all that was proceeding. Almost before he could look down again a shadow went by, and a cuckoo flew along very low, just over the drinking place.

"Cuckoo!" he cried, "cuckoo! The goldfinch has the prettiest dress;" and off he went.

Now the hawk had bribed the cuckoo, who was his cousin, to do this, and the cuckoo was not at all unwilling, for he had an interest himself in keeping the birds divided, so he said that although he had made up his mind to go on his summer tour, leaving his children to be taken care of by the wagtail, he would stop a day or two longer to manage this little business. No sooner had the cuckoo said this, than there was a most terrible uproar, and all the birds cried out at once. The blackbird was so disgusted that he flew straight off, chattering all across the field and up the hedge. The bullfinch tossed his head, and asked the goldfinch to come up in the bush and see which was stronger. The greenfinch and the chaffinch shrieked with derision; the wood-pigeon turned his back and said "Pooh!" and went off with a clatter. The sparrow flew to tell his mates on the house, and you could hear the chatter they made about it right down at the brook. But the wren screamed loudest of all, and said that the goldfinch was a painted impostor, and had not got half so much gold as the yellow-hammer. So they were all scattered in a minute, and Bevis stood up and hurried homeward.

THE LOON

(FROM WALDEN.)

BY HENRY D. THOREAU.

It is remarkable how many creatures live wild and free, though secret, in the woods, and still sustain themselves in the neighborhood of towns, suspected by hunters only. How retired the otter manages to live here! He grows to be four feet long, as big as a small boy, perhaps without any human being getting a glimpse of him. I formerly saw the raccoon in the woods behind where my house is built, and probably still heard their whinnering at night. Commonly I rested an hour or two in the shade at noon, after planting, and ate my lunch, and read a little by a spring which was the source of a swamp and of a brook, oozing from under Brister's Hill, half a mile from my field. The approach to this was through a succession of descending grassy hollows, full of young pitch-pines, into a larger wood about the swamp.

There, in a very secluded and shaded spot, under a spreading white-pine, there was yet a clean, firm sward to sit on. I had dug out the spring and made a well of clear gray water, where I could dip up a pailful without roiling it, and thither I went for this purpose almost every day in midsummer, when the pond was warmest. Thither, too, the wood-cock led her brood, to probe the mud for worms, flying but a foot above them down the bank, while they ran in a troop beneath; but at last, spying me, she would leave her young and circle round and round me, nearer and nearer till within four or five feet, pretending broken wings and legs, to attract my attention, and get off her young, who would already have taken up their march, with faint wiry peep, single file through the swamp, as she directed. Or I heard the peep of the young when I could not see the parent bird.

There, too, the turtle-doves sat over the spring, or fluttered from bough to bough of the soft white-pines over, my head; or the red squirrel, coursing down the nearest bough, was particularly familiar and inquisitive. You only need sit still long enough in some attractive spot in the woods that all its inhabitants may exhibit themselves to you by turns....

In the fall the loon (_Colymbus glacialis_) came, as usual, to moult and bathe in the pond, making the woods ring with his wild laughter before I had risen. At rumor of his arrival all the Mill-dam sportsmen are on the alert, in gigs and on foot, two by two and three by three, with patent rifles and conical balls and spy-glasses. They come rustling through the woods like autumn leaves, at least ten men to one loon. Some station themselves on this side of the pond, some on that, for the poor bird cannot be omnipresent; if he dive here he must come up there.

But now the kind October wind rises, rustling the leaves and rippling the surface of the water, so that no loon can be heard or seen, though his foes sweep the pond with spy-glasses, and make the woods resound with their discharges. The waves generously rise and dash angrily, taking sides with all waterfowl, and our sportsmen must beat a retreat to town and shop and unfinished jobs. But they were too often successful. When I went to get a pail of water early in the morning I frequently saw this stately bird sailing out of my cove within a few rods. If I endeavored to overtake him in a boat, in order to see how he would manoeuvre, he would dive and be completely lost, so that I did not discover him again, sometimes, till the latter part of the day. But I was more than a match for him on the surface. He commonly went off in a rain.

As I was paddling along the north shore one very calm October afternoon, for such days especially they settle on to the lakes, like the milkweed down, having looked in vain over the pond for a loon, suddenly one, sailing out from the shore toward the middle a few rods in front of me, set up his wild laugh and betrayed himself. I pursued with a paddle and he dived, but when he came up I was nearer than before. He dived again but I miscalculated the direction he would take, and we were fifty rods apart when he came to the surface this time, for I had helped to widen the interval; and again he laughed long and loud, and with more reason than before.

He manoeuvred so cunningly that I could not get within half a dozen rods of him. Each time when he came to the surface, turning his head this way and that, he coolly surveyed the water and the land, and apparently chose his course so that he might come up where there was the widest expanse of water and at the greatest distance from the boat. It was surprising how quickly he made up his mind and put his resolve into execution. He led me at once to the wildest part of the pond, and could not be driven from it. While he was thinking one thing in his brain, I was endeavoring to divine his thought in mine. It was a pretty game, played on the smooth surface of the pond, a man against a loon.

Suddenly your adversary's checker disappears beneath the board, and the problem is to place yours nearest to where his will appear again. Sometimes he would come up unexpectedly on the opposite side of me, having apparently passed directly under the boat. So long-winded was he and so unweariable, that when he had swam farthest he would immediately plunge again, nevertheless; and then no wit could divine where in the deep pond, beneath the smooth surface, he might be speeding his way like a fish, for he had time and ability to visit the bottom of the pond in its deepest part. It is said that loons have been caught in the New York lakes eighty feet beneath the surface, with hooks set for trout,--though Walden is deeper than that. How surprised must the fishes be to see this ungainly visitor from another sphere speeding his way amid their schools!

Yet he appeared to know his course as surely under water as on the surface, and swam much faster there. Once or twice I saw a ripple where he approached the surface, just put his head out to reconnoitre, and instantly dived again. I found that it was as well for me to rest on my oars and wait his reappearing as to endeavor to calculate where he would rise; for again and again, when I was straining my eyes over the surface one way, I would suddenly be startled by his unearthly laugh behind me. But why, after displaying so much cunning, did he invariably betray himself the moment he came up by that loud laugh? Did not his white breast enough betray him?

He was indeed a silly loon, I thought. I could commonly hear the plash of the water when he came up, and so also detected him. But after an hour he seemed as fresh as ever, dived as willingly and swam yet farther than at first. It was surprising to see how serenely he sailed off with unruffled breast when he came to the surface, doing all the work with his webbed feet beneath. His usual note was this demoniac laughter, yet somewhat like that of a waterfowl; but occasionally when he had balked me most successfully and come up a long way off, he uttered a long-drawn unearthly howl, probably more like that of a wolf than any bird; as when a beast puts his muzzle to the ground and deliberately howls. This was his looning,--perhaps the wildest sound that is ever heard here, making the woods ring far and wide. I concluded that he laughed in derision of my efforts, confident of his own resources.

Though the sky was by this time overcast, the pond was so smooth that I could see where he broke the surface when I did not hear him. His white breast, the stillness of the air, and the smoothness of the water were all against him. At length, having come up fifty rods off, he uttered one of those prolonged howls, as if calling on the god of loons to aid him, and immediately there came a wind from the east and rippled the surface, and filled the whole air with misty rain, and I was impressed as if it were the prayer of the loon answered, and his god was angry with me; and so I left him disappearing far away on the tumultuous surface.

For hours, in fall days, I watched the ducks cunningly tack and veer and hold the middle of the pond, far from the sportsman; tricks which they will have less need to practise in Louisiana bayous. When compelled to rise they would sometimes circle round and round and over the pond at a considerable height, from which they could easily see to other ponds and the river, like black motes in the sky; and, when I thought they had gone off thither long since, they would settle down by a slanting flight of a quarter of a mile on to a distant part which was left free; but what beside safety they got by sailing in the middle of Walden I do not know, unless they love its water for the same reason that I do.

THE DARTMOOR PONIES, OR THE WANDERINGS OF THE HORSE TRIBE

(FROM "THROUGH MAGIC GLASSES.")

BY ARABELLA B. BUCKLEY.

I want you to take a journey with me which I took in imagination a few days ago, as I lay on my back on the sunny moor and watched the Dartmoor ponies.

It was a calm misty morning one day last week, giving promise of a bright and sunny day, when I started off for a long walk across the moor to visit the famous stone-circles, many of which are to be found not far off the track, called Abbot's Way, leading from Buckfast Abbey, on the Dart, to the Abbey of Tavistock, on the Tavy.

My mind was full of the olden times as I pictured to myself how, seven hundred years or more ago, some Benedictine monk from Tavistock Abbey, in his black robe and cowl, paced this narrow path on his way to his Cistercian brethren at Buckfast, meeting some of them on his road as they wandered over the desolate moor in their white robes and black scapularies in search of stray sheep. For the Cistercians were shepherds and wool-weavers, while the Benedictines devoted themselves to learning, and the track of about twenty-five miles from one abbey to the other, which still remains, was worn by the members of the two communities and their dependents, the only variety in whose lives consisted probably in these occasional visits one to the other.

Yet even these monks belonged to modern times compared to the ancient Britons who raised the stone-circles, and buried their dead in the barrows scattered here and there over the moor; and my mind drifted back to the days when, long before that pathway was worn, men clad in the skins of beasts hunted wild animals over the ground on which I was treading, and lived in caves and holes of the ground.

I wondered, as I thought of them, whether the cultured monks and the uncivilized Britons delighted as much in the rugged scenery of the moor as I did that morning. For many miles in front of me the moor stretched out wild and treeless; the sun was shining brightly upon the mass of yellow furze and deep-red heather, drawing up the moisture from the ground, and causing a kind of watery haze to shimmer over the landscape; while the early mist was rising off the _tors_, or hill-tops, in the distance, curling in fanciful wreaths around the rugged and stony summits, as it dispersed gradually in the increasing heat of the day.

The cattle which were scattered in groups here and there feeding on the dewy grass were enjoying the happiest time of the year. The moor, which in winter affords them scarcely a bare subsistence, is now richly covered with fresh young grass, and the sturdy oxen fed solemnly and deliberately, while the wild Dartmoor ponies and their colts scampered joyously along, shaking their manes and long flowing tails, and neighing to each other as they went; or clustered together on some verdant spot, where the colts teased and bit each other for fun, as they gambolled round their mothers.

It was a pleasure, there on the open moor, with the lark soaring overhead, and the butterflies and bees hovering among the sweet-smelling furze blossoms, to see horses free and joyous, with no thought of bit or bridle, harness or saddle, whose hoofs had never been handled by the shoeing-smith, nor their coats touched with the singeing iron. Those little colts, with their thick heads, shaggy coats, and flowing tails, will have at least two years more freedom before they know what it is to be driven or beaten. Only once a year are they gathered together, claimed by their owners and branded with an initial, and then left again to wander where they will. True, it is a freedom which sometimes has its drawbacks, for if the winter is severe the only food they can get will be the furze-tops, off which they scrape the snow with their feet; yet it is very precious in itself, for they can gallop when and where they choose, with head erect, sniffing at the wind and crying to each other for the very joy of life.

Now as I strolled across the moor and watched their gambols, thinking how like free wild animals they seemed, my thoughts roamed far away, and I saw in imagination scenes where other untamed animals of the horse tribe are living unfettered all their lives long.

First there rose before my mind the level grass-covered pampas of South America, where wild horses share the boundless plains with troops of the rhea, or American ostrich, and wander, each horse with as many mares as he can collect, in companies of hundreds or even thousands in a troop. These horses are now truly wild, and live freely from youth to age, unless they are unfortunate enough to be caught in the more inhabited regions by the lasso of the hunter. In the broad pampas, the home of herds of wild cattle, they dread nothing. There, as they roam with one bold stallion as their leader, even beasts of prey hesitate to approach them, for, when they form into a dense mass with the mothers and young in their centre, their heels deal blows which even the fierce jaguar does not care to encounter, and they trample their enemy to death in a very short time. Yet these are not the original wild horses we are seeking, they are the descendants of tame animals, brought from Europe by the Spaniards to Buenos Ayres in 1535, whose descendants have regained their freedom on the boundless pampas and prairies.

As I was picturing them careering over the plains, another scene presented itself and took their place. Now I no longer saw around me tall pampas-grass with the long necks of the rheas appearing above it, for I was on the edge of a dreary, scantily covered plain between the Aral Sea and the Balkash Lake in Tartary. To the south lies a barren sandy desert, to the north the fertile plains of the Kirghiz steppes, where the Tartar feeds his flocks, and herds of antelopes gallop over the fresh green pasture; and between these is a kind of no-man's land, where low scanty shrubs and stunted grass seem to promise but a poor feeding-ground.

Yet here the small long-legged but powerful "Tarpans," the wild horses of the treeless plains of Russia and Tartary, were picking their morning meal. Sturdy wicked little fellows they are, with their shaggy light-brown coats, short wiry manes, erect ears, and fiery watchful eyes. They might well be supposed to be true wild horses, whose ancestors had never been tamed by man; and yet it is more probable that even they escaped in early times from the Tartars, and have held their own ever since, over the grassy steppes of Russia and on the confines of the plains of Tartary. Sometimes they live almost alone, especially on the barren wastes where they have been seen in winter, scraping the snow off the herbage as our ponies do on Dartmoor. At other times, as in the south of Russia, where they wander between the Dnieper and the Don, they gather in vast herds and live a free life, not fearing even the wolves, which they beat to the ground with their hoofs. From one green oasis to another they travel over miles of ground.

"A thousand horse--and none to ride! With flowing tail, and flying mane, Wide nostrils--never stretched by pain, Mouths bloodless to the bit or rein, And feet that iron never shod, And flanks unscarred by spur or rod, A thousand horse, the wild, the free, Like waves that follow o'er the sea."[11]

[11] Byron's _Mazeppa_.

As I followed them in their course I fancied I saw troops of yet another animal of the horse tribe, the "Kulan," or _Equus hemionus_, which is a kind of half horse, half ass (p. 393), living on the Kirghiz steppes of Tartary and spreading far beyond the range of the Tarpan into Tibet. Here at last we have a truly wild animal, never probably brought into subjection by man. The number of names he possesses shows how widely he has spread. The Tartars call him "Kulan," the Tibetans "Kiang," while the Mongolians give him the unpronounceable name of "Dschiggetai." He will not submit to any of them, but if caught and confined soon breaks away again to his old life, a "free and fetterless creature."

No one has ever yet settled the question whether he is a horse or an ass, probably because he represents an animal truly between the two. His head is graceful, his body light, his legs slender and fleet, yet his ears are long and ass-like; he has narrow hoofs, and a tail with a tuft at the end like all the ass tribe; his color is a yellow brown, and he has a short dark mane and a long dark stripe down his back as a donkey has, though this last character you may also see in many of our Devonshire ponies. Living often on the high plateaux, sometimes as much as fifteen hundred feet above the sea, this "child of the steppes" travels in large companies even as far as the rich meadows of Central Asia; in summer wandering in green pastures, and in winter seeking the hunger-steppes where sturdy plants grow. And when autumn comes the young steeds go off alone to the mountain heights to survey the country around and call wildly for mates, whom, when found, they will keep close to them through all the next year, even though they mingle with thousands of others.

Till about ten years ago the _Equus hemionus_ was the only truly wild horse known, but in the winter of 1879-80 the Russian traveller Przevalsky brought back from Central Asia a much more horse-like animal, called by the Tartars "Kertag" and by the Mongols "Statur." It is a clumsy, thick-set, whitish-gray creature with strong legs and a large, heavy, reddish-colored head; its legs have a red tint down to the knees, beyond which they are blackish down to the hoofs. But the ears are small, and it has the broad hoofs of the true horse, and warts on his hind legs, which no animal of the ass tribe has. This horse, like the Kiang, travels in small troops of from five to fifteen, led through the wildest parts of the Dsungarian desert, between the Altai and Tianschan Mountains, by an old stallion. They are extremely shy, and see, hear, and smell very quickly, so that they are off like lightning whenever anything approaches them.

So having travelled over America, Europe, and Asia, was my quest ended? No; for from the dreary Asiatic deserts my thoughts wandered to a far warmer and more fertile land, where between the Blue Nile and the Red Sea rise the lofty highlands of Abyssinia, among which the African wild ass (_Asinus taeniopus_), the probable ancestor of our donkeys, feeds in troops on the rich grasses of the slopes, and then onwards to the bank of a river in Central Africa where on the edge of a forest, with rich pastures beyond, elephants and rhinoceroses, antelopes and buffaloes, lions and hyaenas, creep down in the cool of the evening to slake their thirst in the flowing stream. There I saw the herds of Zebras in all their striped beauty coming down from the mountain regions to the north, and mingling with the darker-colored but graceful quaggas from the southern plains, and I half-grieved at the thought how these untamed and free rovers are being slowly but surely surrounded by man closing in upon them on every side.

I might now have travelled still farther in search of the Onager, or wild ass of the Asiatic and Indian deserts, but at this point a more interesting and far wider question presented itself, as I flung myself down on the moor to ponder over the early history of all these tribes.

Where have they all come from? Where shall we look for the first ancestors of these wild and graceful animals? For the answer to this question I had to travel back to America, to those Western United States where Professor Marsh has made such grand discoveries in horse history. For there, in the very country where horses were supposed never to have been before the Spaniards brought them a few centuries ago, we have now found the true birthplace of the equine race.

Come back with me to a time so remote that we cannot measure it even by hundred of thousands of years, and let us visit the territories of Utah and Wyoming. Those highlands were very different then from what they are now. Just risen out of the seas of the Cretaceous Period, they were then clothed with dense forests of palms, tree-ferns, and screw-pines, magnolias and laurels, interspersed with wide-spreading lakes, on the margins of which strange and curious animals fed and flourished. There were large beasts with teeth like the tapir and the bear, and feet like the elephant; and others far more dangerous, half bear, half hyaena, prowling around to attack the clumsy paleotherium or the anoplotherium, something between a rhinoceros and a horse, which grazed by the waterside, while graceful antelopes fed on the rich grass. And among these were some little animals no bigger than foxes, with four toes and a splint for the fifth, on their front feet, and three toes on the hind ones.

These clumsy little animals, whose bones have been found in the rocks of Utah and Wyoming, have been called _Eohippus_, or horses of the dawn, by naturalists. They were animals with real toes, yet their bones and teeth show that they belonged to the horse tribe, and already the fifth toe common to most other toed animals was beginning to disappear.

This was in the Eocene Period, and before it passed away with its screw-pines and tree-ferns, another rather larger animal, called the Orohippus, had taken the place of the small one, and he had only four toes on his front feet. The splint had disappeared, and as time went on still other animals followed, always with fewer toes, while they gained slender fleet legs, together with an increase in size and in gracefulness. First one as large as a sheep (Mesohippus) had only three toes and a splint. Then the splint again disappeared, and one large and two dwindling toes only remained, till finally these two became mere splints, leaving one large toe or hoof with almost imperceptible splints, which may be seen on the fetlock of a horse's skeleton.

You must notice that a horse's foot really begins at the point which we call his knee in the front legs, and at his hock in his hind legs. His true knee and elbow are close up to the body. What we call his foot or hoof is really the end of the strong, broad, middle toe covered with a hoof, and farther up his foot we can feel two small splints, which are remains of two other toes.

Meanwhile during these long succeeding ages while the foot was lengthening out into a slender limb the animals became larger, more powerful, and more swift, the neck and head became longer and more graceful, the brain-case larger in front and the teeth decreased in number, so that there is now a large gap between the biting teeth and the grinding teeth of a horse. Their slender limbs too became more flexible and fit for running and galloping, till we find the whole skeleton the same in shape, though not in size, as in our own horses and asses now.

They did not, however, during all this time remain confined to America, for, from the time when they arrived at an animal called _Miohippus_, or lesser horse, which came after the Mesohippus and had only three toes on each foot, we find their remains in Europe, where they lived in company with the giraffes, opossums, and monkeys which roamed over these parts in those ancient times. Then a little later we find them in Africa and India; so that the horse tribe, represented by creatures about as large as donkeys, had spread far and wide over the world.

And now, curiously enough, they began to forsake, or to die out in, the land of their birth. Why they did so we do not know; but while in the old world as asses, quaggas, and zebras, and probably horses, they flourished in Asia, Europe, and Africa, they certainly died out in America, so that ages afterwards, when that land was discovered, no animal of the horse tribe was found in it.

And the true horse, where did he arise? Born and bred probably in Central Asia from some animal like the "Kulan," or the "Kertag," he proved too useful to savage tribes to be allowed his freedom, and it is doubtful whether in any part of the world he escaped subjection. In our own country he probably roamed as a wild animal till the savages, who fed upon him, learned in time to put him to work; and when the Romans came they found the Britons with fine and well-trained horses.

Yet though tamed and made to know his master, he has, as we have seen, broken loose again in almost all parts of the world--in American on the prairies and pampas, in Europe and Asia on the steppes, and in Australia in the bush. And even in Great Britain, where so few patches of uncultivated land still remain, the young colts of Dartmoor, Exmoor, and Shetland, though born of domesticated mothers, seems to assert their descent from wild and free ancestors as they throw out their heels and toss up their heads with a shrill neigh, and fly against the wind with streaming manes and outstretched tails as the Kulan, the Tarpan, and the Zebra do in the wild desert or grassy plain.

NOTES

ALLEN, GRANT, English scientist and man of letters; born 1848, died 1899. Was born in Canada, and passed his boyhood there. Educated in France and at Oxford University. He wrote "Physiological AEsthetics," "Vignettes from Nature," "The Evolutionist at Large," "Force and Energy," many scientific papers in periodicals, and some fiction. "Strange Stories," "The Reverend John Creedy," "Philistia," "The British Barbarians" among others.

BELT, T. G., an English traveller of the nineteenth century, best known by his book, "The Naturalist in Nicaragua."

BLATCHLEY, W. S., American naturalist and geologist, born 1859. Has taken part in many important geological surveys, and is State geologist of Indiana. Among his writings are "Gleanings from Nature," and many important highly technical contributions to State scientific publications.

BRUNER, L., American professor of entomology and ornithology at the University of Nebraska, born 1566. Is the State entomologist of Nebraska. Has written "An Introduction to the Study of Entomology," and some papers on the locusts of Argentina, as well as many technical scientific reports in State papers, etc.

BURROUGHS, JOHN, American essayist, born 1837. Has written much on nature observation. Among his books are "Wake Robin," "Winter Sunshine," "Birds and Poets," "Pepacton," "Fresh Fields," "Signs and Seasons," etc. He was at first a school teacher, then a clerk of the treasury, then a national bank examiner, and he now lives on a farm, devoting himself to literature and fruit culture.

HOPLEY, MRS. C. C., an English author who lived much in America, and made a special study of "Snakes," on which subject she wrote a great deal. Her book entitled "Snakes" is the most important record of her work.

HUXLEY, T. H., Famous English biologist, born 1825; died 1895. Was assistant surgeon in the navy, then professor of natural history, rector of Aberdeen University, and president of the Royal Society. Among his books are, "Evidences as to Man's Place in Nature," "Comparative Anatomy," "Lay Sermons," "Critiques and Addresses," "Physiography," "The Crayfish," "Science and Culture," "Evolution and Ethics," "The Anatomy of Invertebrate Animals," etc.

JEFFERIES, RICHARD, born near Swindon, Wiltshire, Nov. 6, 1848; died Aug. 14, 1887. A naturalist whose fascinating writings were recognized as classics only after his death. Among his most popular books are, "The Gamekeeper at Home" (1878), "Wild Life in a Southern Country" (1879), "The Amateur Poacher" (1880), "Round About a Great Estate" (1881), "Nature Near London," and "The Story of My Heart" (1883), "Red Deer" (1884), and "The Open Air" (1885).

JORDAN, DAVID STARR, President Leland Stanford, Jr., University; born Gainesville, N.Y., Jan. 19, 1851; graduated Cornell M. S., 1872; M. D. Indiana Medical College, 1875; (Ph.D. Butler University, 1878; LL.D. Cornell University, 1886). Held chairs in various collegiate institutions, 1872-79; assistant to U. S. Fish Commission, 1877-91; professor of zooelogy 1879-85, and president 1885-91, Indiana University; president Leland Stanford Jr., University since 1891; president California Academy of Sciences 1896-98; also U. S. Commissioner in charge of fur-seal investigations, etc. Author: "A Manual of Vertebrate Animals of Northern United States," "Science Sketches," "Fishes of North and Middle America" (4 vols.); "Footnotes to Evolution," "Matka and Kotik," "Care and Culture of Men," "The Innumerable Company," "Imperial Democracy," "Animal Life," "Animal Forms," "The Strength of Being Clean," "Standeth God within the Shadow," also numerous papers on Ichthyology, in procedures of various societies and government bureaus.

MAETERLINK, MAURICE, Belgian dramatist and poet, born 1864. He began early to write plays, which were translated into English and represented in London. He has written "Le Tresor des Humbles," "Aglavaine and Selysette," "Pelleas and Melisande," "The Intruder," "Princess Maleine," "Wisdom and Destiny." He has been called the "Belgian Shakespeare."

MORLEY, MARGARET W., author and teacher, born 1858. Has taught in New York State and in the West. She is the author of "A Song of Life," "Life and Love," "A Few Familiar Flowers," "Flowers and their Friends," "The Bee People," "The Honey Makers," "Seed Babies," "Little Wanderers," "Wasps and their Ways," etc.

THOREAU, HENRY DAVID, born at Concord, Mass., July 12, 1817; died May 6, 1862. After his graduation from Harvard, in 1837, he helped his father make lead pencils. In 1839 he began his careful studies on nature, and made a voyage on the Concord and Merrimac Rivers described in his first book. His most popular work, "Walden, or Life in the Woods," was published in 1854. After his death several volumes were made up from his voluminous diaries. His collected writings, in ten volumes, were published in 1893.

WALLACE, A. R., noted English naturalist and traveller, born 1822. Was educated as a land surveyor, but turned his attention exclusively to natural history. He explored the valleys of the Amazon and Rio Negro, travelled in the Malay Archipelago and Papua. He and Darwin both announced together the theory of natural selection. He wrote "Travels on the Amazon," "Palm Trees of the Amazon," "The Malay Archipelago," "Contributions to the Theory of Natural Selection," "Geographical Distribution of Animals," "Tropical Nature," "Island Life," etc.

WILSON, A., English physiologist, lecturer, and journalist, born 1852. Educated Edinburgh University and Medical School. Has written much on popular physiology in the newspapers and magazines. Is the author of "Studies on Life," "Leisure Time Studies," "Science Stories," "Chapters on Evolution," "Leaves from a Naturalist's Note Book," "Wild Animals," "Elements of Zooelogy," etc.

NATURAL HISTORY

SUGGESTIONS FOR SUPPLEMENTARY READINGS

Days Out of Doors CHARLES C. ABBOTT

First Lessons in Zooelogy ELIZABETH C. AGASSIZ

Birds of America JOHN J. AUDUBON

My Land and Water Friends M. E. BAMFORD

Locusts and Wild Honey JOHN BURROUGHS

Woodlands MORDECAI C. COOK

A Year Among the Birds WILSON FLAGG

The Out Door World W. FURNEAUX

The Great World's Farm SELINA GAYE

Monsters of the Sea Chips from the Earth's Crust J. GIBSON

Sharp Eyes WILLIAM H. GIBSON

Practical Forestry JOHN GIFFORD

Along the Florida Reefs CHARLES F. HOLDER

About Pebbles ALPHEUS HYATT

Country Cousins ERNEST INGERSOLL

History of a Mouthful of Bread JEAN MACE

Under Foot L. D. NICHOLLS

Underground Treasures JAMES ORTON

Among the Night People C. D. PIERSON

Ethics of the Dust JOHN RUSKIN

The Sea Children WALTER RUSSELL

Aspects of the Earth NATHANIEL S. SHALER

The Vacation Club ADA J. TODD

The Complete Angler IZAAK WALTON

Half Hours in Field and Forest Half Hours with a Naturalist J. G. WOOD