Part 16
"Although this animal be not very tremendous for its size, nor very terrific in its appearance, it is the very same whose ravages have been the theme of naturalists and historians in all ages, and upon a close examination you will find it to be peculiarly fitted and furnished for the execution of its office. It is armed with two pairs of very strong jaws, the upper terminating in short, and the lower in long teeth, by which it can both lacerate and grind its food; its stomach is of extraordinary capacity and powers; its hind legs enable it to leap to a considerable distance, and its ample vans are calculated to catch the wind as sails, and so to carry it sometimes over the sea; and although a single individual can effect but little evil, yet when the entire surface of a country is covered by them, and every one makes bare the spot on which it stands, the mischief produced may be as infinite as their numbers. So well do the Arabians know their power, that they make a Locust say to Mahomet, 'We are the army of the Great God; we produce ninety-nine eggs; if the hundred were completed, we should consume the whole earth and all that is in it.'"
3. NEUROPTERA (Nerve-winged).
The Neuroptera comprise the Dragon-fly (Libellulina, fig. 16), Ant-lion (Myrmelion), Caddis-flies (Phryganidæ), and the May-flies (Ephemera); these insects have wings of a beautiful network structure, as may be seen in the Dragon-fly, they make their appearance about the middle of June in the locality of ditches and ponds. The Caddis-fly is noted for the peculiar case which the larva makes for itself; the larva inhabits the water and the ease is made of little fragments of wood, shell, and sand, agglutinated together so as to float; the perfect insect is not aquatic, and flies away when formed. The May-flies are noted for the shortness of their existence, the larvæ live in the water, and many of them are eaten by fishes who are very fond of them, but sufficient numbers come to the perfect state, to form complete clouds in the air where the larvæ were, these creatures live but a day, and some of their species but an hour or two, in the perfect state, they deposit their eggs in the water, which come to life in the mud at the bottom. The flight of these fragile beings and their short-lived holiday festivities are well described by Kirby and Spence:--
"In the beginning of September, for two successive years, I was so fortunate as to witness a spectacle of this kind, which afforded me a more sublime gratification than any work or exhibition of art has power to communicate. The first was in 1811. Taking an evening walk near my house, when the sun, declining fast towards the horizon, shone forth without a cloud, the whole atmosphere over and near the stream swarmed with infinite myriads of Ephemeræ and little gnats of the genus chironomus, which in the sun-beam appeared as numerous and more lucid than the drops of rain, as if the heavens were showering down brilliant gems. Afterwards, in the following year, one Sunday, a little before sunset, I was enjoying a stroll with a friend at a greater distance from the river, when in a field by the road-side the same pleasing scene was renewed, but in a style of still greater magnificence; for, from some cause in the atmosphere, the insects at a distance looked much larger than they really were. The choral dances consisted principally of Ephemeræ, but there were also some chironomi, the former, however, being most conspicuous, attracted our chief attention. Alternately rising and falling, in the full beam they appeared so transparent and glorious, that they scarcely resembled anything material; they reminded us of angels and glorified spirits drinking life and joy in the effulgence of the Divine favour. The Bard of Twickenham, from the terms in which his beautiful description of his sylphs is conceived in the 'Rape of the Lock' seems to have witnessed the pleasing scene here described:--
'Some to the sun their insect wings unfold, Waft on the breeze, or sink in clouds of gold; Transparent forms, too fine for mortal sight, Their fluid bodies half dissolved in light; Loose to the wind their airy garments flew, Thin glittering textures of the filmy dew, Dipt in the richest tincture of the skies, Where light disports in ever mingling dyes, While every beam new transient colours flings, Colours that change whene'er they wave their wings.'"
4. HYMENOPTERA (Membrane-winged).
The Hymenoptera are those insects which have four membraneous wings. The Bees (Apidæ, fig. 16), Wasps (Vespidæ), the Ants (Formicidæ), and the Ichneumon Flies (Ichneumonidæ), are the chief tribes of this order. The Bees, Wasps, and Ants are celebrated for forming societies, more perfectly arranged and governed than in any other creatures but man. It is curious that the most perfect instincts (such as approach so nearly to reason that they almost defy us to make a distinction) should have been given by the Creator to creatures so far removed from man in the scale of existence, and so little resembling him in any other particular. This is one of the stumbling-blocks in the way of those who wish to have it believed that all animals are progressive from certain types, which cannot be got over; if such were the case, man would be most nearly imitated by the Apes, and these again by those most nearly allied to them, and so on downwards, but here we find a government almost as perfect as that of the human species--an arrangement of work, a division of labour, buildings, storehouses, &c.--showing nearly all the social habits and feelings of man, in creatures who in form and size have no resemblance to him.
Kirby and Spence, in describing the societies of insects, say:--"But when we consider the object of these societies, the preservation and multiplication of the species, and the means by which that object is attained (the united labours and co-operation of perhaps millions of individuals), it seems as if they were impelled by passions very similar to those main-springs of human associations which I have just enumerated. Desire appears to stimulate them, love to allure them, fear to alarm them. They want a habitation to reside in and food for their subsistence. Does not this look as if desire were the operating cause which induces them to unite their labours to construct the one and provide the other? Their nest contains a numerous family of helpless brood. Does not love here seem to urge them to exemplary and fond attention, and those unremitted and indefatigable exertions manifested by the whole community for the benefit of these dear objects? Is it not also evident by their general and singular attachment to their families, by their mutual caresses, by their feeding each other, by their sympathy with suffering individuals and endeavours to relieve them, by their readiness to help those that are in difficulty, and finally by their sports and assemblies for relaxation? That fear produces its influences upon them seems no less evident, when we see them agitated by the approach of enemies, endeavour to repel their attacks, and to construct works of defence. They appear to have besides a common language, for they possess the faculty, by significative gestures and sounds, of communicating their wants and ideas to each other."
Numerous works have been entirely devoted to the habits and instincts of Bees and Ants, and very interesting they are, but it would be impossible to give an intelligible account of them in the small space allotted in this volume.
The wax of which Bees build their beautiful six-sided cells, and which is the whole source of all the wax used by men for a variety of purposes, is secreted in little scales or flakes, between the joints of the abdomen, from whence the wax-making Bees take it to build the comb; the cells of the comb are filled with honey, which is obtained by the Bees (by means of the apparatus shown at fig. 23), from the nectaries of flowers in the form of nectar, and is converted into honey in the honey-bag of the Bee, from whence it is discharged into the cells. Bees also collect the pollen from the flowers they visit, this adheres to the hairs on the Bee, and is scraped and brushed off, and collected into two little lots, which the Bee carries on each hind leg, this pollen is made into bee-bread. By scattering the pollen, flowers are often fecundated, for there are many plants, the female flowers of which are separate from the males, and it is only by insects and the wind, that the females are fecundated, for the Bee, with the pollen adhering to every part, first visits one flower and then another in search of nectar.
With respect to the Ants, Kirby and Spence give the following account of the building of their habitations,
"The nest of _Formica brunnea_ is composed wholly of earth, and consists of a great number of stories, sometimes not fewer than forty, twenty below the level of the soil, and as many above, which last, following the slope of the ant-hill, are concentric. Each story, separately examined, exhibits cavities in the shape of saloons, narrower apartments, and long galleries which preserve the communication between both. The arched roofs of the most spacious rooms are supported by very thin walls, or occasionally by small pillars and true buttresses; some having only one entrance from above, others a second, communicating with the lower story; the main galleries, of which, in some places, several meet in one large saloon, communicate with other subterranean passages, which are often carried to the distance of several feet from the hill. These insects work chiefly after sunset. In building their nest they employ soft clay only, scraped from its bottom when sufficiently moistened by a shower, which, far from injuring, consolidates and strengthens their architecture. Different labourers convey small masses of this ductile material between their mandibles, and with the same instrument they spread and mould it to their will, the antennæ accompanying every movement. They render all firm by pressing the surface lightly with their fore feet; and however numerous the distinct masses of clay composing these walls, and though connected by no glutinous material, they appear when finished, one single layer, well united, consolidated and smoothed. Having traced the plan of their structure, by placing here and there the foundations of the pillars and partition-walls, they add successively new portions; and when the walls of a gallery or apartment, which are half a line thick, are elevated about half an inch in height, they join them by springing a flattish arch or roof from one side to the other. Nothing can be a more interesting spectacle than one of these cities while building. In one place vertical walls form the outline, which communicate with different corridors by openings made in the masonry; in another we see a true saloon, whose vaults are supported by numerous pillars; and further on are the cross-ways or squares where several streets meet, and whose roofs, though often more than two inches across, the Ants are under no difficulty in constructing, beginning the sides of the arch in the angle formed by two walls, and extending them by successive layers of clay till they meet; while crowds of masons arrive from all parts with their particles of mortar, and work with a regularity, harmony, and activity, which can never enough be admired. So assiduous are they in their operations, that they will complete a story with all its saloons, vaulted roofs, partitions and galleries, in seven or eight hours. If they begin a story, and for want of moisture are unable to finish it, they pull down again all the crumbling apartments that are not covered in."
Every one has heard of the destructive as well as constructive qualities of the "White Ant;" another quotation from Kirby and Spence will illustrate both.
"When they find their way into houses or warehouses nothing less hard than metal or glass escapes their ravages; their favourite food, however, is wood of all kinds, except the Teak, and Ironwood, which are the only sorts known, that they will not touch; and so infinite are the multitudes of the assailants, and such is the excellence of their tools, that all the timber-work of a spacious apartment is often destroyed by them in a few nights. Exteriorly, however, everything appears as if untouched; for these wary depredators (and this is what constitutes the greatest singularity of their history) carry on all their operations by sap and mine, destroying utterly the inside of solid substances, and scarcely ever attacking their outside until they have first concealed it and their operations with a coating of clay. A general similarity runs through the proceedings of the whole tribe, but the large African species, called by Smeathman Termes bellicosus, is the most formidable. These insects live in large clay nests, from whence they excavate tunnels all round, often to the extent of several hundred feet; from these they will descend a considerable depth below the foundation of a house, and rise again through the floors; or, boring through the posts and supports of the building, enter the roof and construct their galleries in various directions.
"If a post be a convenient path to the roof, or has any weight to support, (how they discover it is not easily conjectured), they will fill it with their mortar, leaving only a track-way for themselves, and thus, as it were, convert it from wood into stone as hard as many kinds of freestone. In this manner they soon destroy houses, and sometimes whole villages, when deserted by their inhabitants, so that in two or three years not a vestige of them will remain. These insidious insects are not less expeditious in destroying the wainscoating, shelves, and other fixtures of a house, than the house itself; with the most consummate art and skill they eat away the inside of what they attack, except a few fibres here and there, which exactly suffice to keep the two sides, or top and bottom, connected, so as to retain the appearance of solidity after the reality is gone; and all the while they carefully avoid perforating the surface, unless a book or any other thing that tempts them should be standing upon it.
"Koempfer, speaking of the White Ants of Japan, gives a remarkable instance of the rapidity with which these miners proceed. Upon rising one morning he observed that one of their galleries of the thickness of his little finger had been formed across his table; and upon a further examination he found that they had bored a passage of that thickness up one foot of the table, formed a gallery across it, and then pierced down another foot into the floor; all this was done in the few hours that intervened between his retiring to rest and his rising."
Most of this order are armed with some weapon of defence. The Bee and Wasp have each a most formidable sting, with which they are able to inflict a wound fatal to most insects. The Ants have a peculiar secretion, consisting of formic acid, which they eject with great force, and which has a very disagreeable smell. The eggs of Ants when hatched produce a small grub, which spins itself a sort of cocoon, and in this state it so much resembles a grain of corn, that it has been mistaken for it; this error has given rise to the supposition that Ants store up corn for winter, whereas they never eat corn, but the care they take of these larvæ, removing them from place to place, taking them up in their mandibles and running along with them, has been mistaken for the act of storing away grains of corn.
5. STREPSIPTERA (Twisted-winged).
This order includes but a few species; Dr. Baird in his Cyclopædia, gives the following account of them:--
"Certain insects were discovered by Kirby, living parasitic in the abdomen of some Andrenæ, which at that time were nondescript, and could not be referred to any existing order. They were afterwards placed in an order by themselves, which he called Strepsiptera. The larvæ live in the bodies of Bees, Wasps &c., and the males only undergo a perfect metamorphosis; the females, even when adult, have neither legs, wings, nor eyes, but resemble larvæ, and continue to live parasitic in the bodies of the Hymenopterous insects within which they were born. The characters are thus taken from the male and consist chiefly in the structure of the wings. The anterior pair are quite rudimentary, being transformed into a pair of short, slender, contorted appendages resembling narrow balancers or halters. The posterior pair are large and membraneous, their nervures are only longitudinal, so that they are able to fold them like a fan. They have large globular eyes, with the facets few, but of comparatively large size."
About ten or twelve species are known, forming a small family, "Stylopidæ." The genus Stylops may be taken as the type, and contain such species as have the tarsi with four points and the antennæ with six."
6. LEPIDOPTERA (Scaly-winged).
This order includes the Butterflies and Moths, they have four wings, which are large and covered with minute scales, which are for the most part of a heart or battledore shape, as in fig. 27. The wings of these insects are many of them beautifully marked and tinged. There are about 12,000 species, by some divided into "diurnal" (or those which fly by day), "crepuscular" (or those which fly in the evening), and "nocturnal" (or those flying by night). The Moths are mostly crepuscular and nocturnal, while the Butterflies are chiefly diurnal, but the most usual distinction between the Moth and Butterfly consists in the form of the antennæ, those of the Moth being feather-shaped, while those of the Butterfly have a small knob at the end, or, as it is called, "club-shaped." The Lepidoptera feed upon the nectar of flowers, for which purpose they are furnished with a long proboscis or "Haustellium," which is curled up under the head, it consists of two semi-cylindrical pieces which when placed side by side form a tube, up which the nectar is drawn by capillary attraction. The metamorphosis of these insects is complete.
The Silkworm (Bombyx mori) belongs to this order. It is the most important of all insects to man, as from it alone all the silk of commerce is obtained. Its cocoon is of a beautiful yellow colour, varying in shade from orange to pale straw-colour; the silk of one cocoon weighs somewhere about three grains; it would therefore, at this calculation, take 1920 worms to spin one pound. The annual import of silk into this country alone is about 7,000,000 pounds, it must therefore take 13,440,000,000 Silkworms to supply us with silk yearly! The Silkworm feeds almost exclusively on the leaves of the mulberry.
7. HEMIPTERA (Half-winged).
The Hemiptera have two pairs of wings, the hindermost small, and the foremost pair half horny and half membraneous, the base being horny, and the apex membraneous. They include the Bugs, some of which are aquatic, as the Water Scorpion (Nepa), and the Water Boatman (Natonecta), which swims on its back, rowing itself by means of a pair of long legs, which look like oars; the common bed Bug is also of this order, although wingless, as are also the Plant Lice (Aphides), which, however, obtain wings in their perfect state.
8. DIPTERA (Two-winged).
The Diptera include the common House Fly (fig. 16), Bluebottle Fly, Gnat, and many others; their wings are like the Neuroptera, but they have but one pair, the other pair being undeveloped, form little knobs called "balancers." The wings of Flies are generally covered with short stout hairs, as seen in fig. 29; the common Fly feeds upon almost anything, but some of the Diptera feed exclusively on the blood of other animals; the Gnat (Culex pipiens), of which the Mosquito is a variety, deposits its egg in the water on any floating substance, the larva which comes from the egg is aquatic, living with its head downwards, the end of the abdomen only being above the water, in this there is a spiracle or breathing orifice, which enables it to take in the air; the Gnat, when it comes from this larva, stands on its shell for a moment, and then flies off, for it is not suited to live in the water; this history of the early stages of its life, accounts for Gnats being always found in such numbers near pools of water. The Tsetse, which Dr. Livingstone describes as being so fatal to cattle, is of this order; he says, "It is well known that the bite of this poisonous insect is certain death to ox, horse, or dog.... A most remarkable feature in the bite of the Tsetse is its perfect harmlessness to man and wild animals, and even calves, so long as they continue to suck the cows."
9. APTERA (Wingless).
To this order belongs the Flea (Pulex irritans), which is furnished with lancet-shaped weapons, through which it sucks the blood of other animals, for it is entirely parasitic, and also the "Chigeo" (Pulex penetrans), which is a troublesome and even dangerous pest in the West Indies; it penetrates the skin of the feet, and deposits its young beneath it.