Part 20

This spring, 1827, fostered into active life an insect unknown in our district, or at least unnoticed before by me; a pretty little blue butterfly, for which I know no common appellation, and so have named it the “spring azure,” (papilio argiolus). It appeared quite at the end of April, and in some numbers, but was yet a transient visitor with us, as after the first week in May only a lingering specimen or so was visible. Few wild flowers are then in bloom; but, leaving all herbaceous plants, it frequented chiefly the holly, the laurel, and the black currant, feeding on the honey secreted by the nectaries in their blossoms. If this butterfly be anywhere common, it may be mistaken by indifferent observers for the little blue argus of our pastures; but it appears some months earlier than that insect is accustomed to do; does not flit from blossom to blossom, and bask upon the disks of the lowly herbs; and, though a feebler creature on the wing, takes a much higher range in flight, and sports in altitudes which the argus, with all its animation, is very rarely inclined to attempt. When in captivity, the dark margins of the upper wings, the black specks, not eyes, and the pale blue of the reverse, without any other character, render it perfectly distinguishable from the papilio argus, corydon, or any other butterfly found with us. A small hatch again takes place about the end of July, and this pretty insect haunts anew our currant bushes; but, enlivened by the warmth of the season, it becomes more wild and wary, and avoids our approach.

The hummingbird hawk-moth (sphinx stellatarum) visits us annually, and occasionally in some numbers, frisking about all the summer long, and in very fine seasons continues with us as late as the second week in October. The vigilance and animation of this creature are surprising, and seem to equal those of its namesake, that splendid meteoric bird of the tropics, “that winged thought,” as some one has called it; though our plain and dusky insect can boast none of its glorious hues. Our little sphinx appears chiefly in the mornings and evenings of the day, rather avoiding the heat of the mid-day sun, possibly roused from its rest by the scent, that “aromatic soul of flowers,” which is principally exhaled at these periods; delighting in the jasmine, marvel of Peru, phlox, and such tubular flowers; and it will even insert its long, flexible tube into every petal of the carnation, to extract the honey- like liquor it contains. It will visit our geraniums and green-house plants, and, whisking over part of them with contemptuous celerity, select some composite flower that takes its fancy, and examine every tube with rapidity, hovering over its disk with quivering wings, while its fine hawklike eyes survey all surrounding dangers. The least movement alarms it, and it darts away with the speed of an arrow; yet returns, and with suspicious vigilance continues its employ, feeding always on the wing. Nature seems to have given this creature some essential requisites for its safety; its activity, when on the wing, renders its capture difficult; and when it rests, it is on a wall, the bark of a tree, or some dusky body, that assimilates so nearly to its own color, as to render it almost invisible, though watched to its settlement; and the larva is seldom found. We sometimes see it enter our rooms, attracted by flowers in the open windows; but it seems to be immediately aware of its danger, disappears in an instant, and is safe from capture. Wild and fearful as this creature is by nature, yet continued gentle treatment will remove much of its timidity, and render it familiar to our presence. Perfectly free from any annoyance as they are when ranging from sweet to sweet on my borders, and accustomed to a close inspection of all their operations, I have frequently touched their wings with my fingers, while hovering over a flower, and dipping their long tubes into the corolla of a geranium: they would retire a little, confused with such freedoms and interruptions, but, experiencing no harm, they would return and finish their meal, unmindful of such petty annoyances. I have known this creature, like some other insects, counterfeit death when apprehensive of danger, fall on its back, and appear in all respects devoid of life when in a box; and, as soon as a fit opportunity arrived, dart away with its usual celerity.

On the blue heads of the pasture scabious (scabiosa succisa) we occasionally see, toward the end of the summer, the painted lady butterfly (papilio cardui); but this is a creature that visits us at very uncertain periods, and is vivified by causes infinitely beyond the comprehension of the entomologist, seeming to require a succession and variety of seasons and their change, and then springing into life we know not how. This was particularly obvious in the summer of 1815, and the two following, which were almost unceasingly cold and rainy; scarcely a moth or butterfly appeared. And in the early part of 1818, the season was not less ungenial; a few half-animated creatures alone struggled into being; yet this “painted lady” was fostered into life, and became the commonest butterfly of the year: it has, however, but very partially visited us since that period. The keenest entomologist, perhaps, would not much lament the absence of this beauty, if such cheerless seasons were always requisite to bring it to perfection. Some years ago a quantity of earth was raised in cutting a canal in this county; and, in the ensuing summer, on the herbage that sprang up from this new soil on the bank, this butterfly was found in abundance, where it had not been observed for many years before.

The marble butterfly (papilio galathea) is an equally capricious visitant of our fields. I have known intervals of ten or twelve years when none could be found, and in some following seasons it would be a prevailing species.

The common wasp (vespa vulgaris) is infinitely uncertain in its numbers. A mild winter, and a dry spring or summer, we might conclude to be favorable circumstances for the increase of this creature; yet such is not always the case. Years productive of the plum are said to be congenial likewise to the wasp. A local rhyme will have it, that

“When the plum hangs on the tree, Then the wasp you’re sure to see.”

Amid the tribes of insects so particularly influenced by seasons, there are a few which appear little affected by common events; the brown meadow butterfly (papilio janira), so well known to every one, I have never missed in any year; and in those damp and cheerless summers, when even the white cabbage butterfly is scarcely to be found, this creature may be seen in every transient gleam, drying its wings, and tripping from flower to flower with animation and life, nearly the sole possessor of the field and its sweets. Dry and exhausting as the summer may be, yet this dusky butterfly is uninjured by it, and we see it in profusion hovering about the sapless foliage. In that arid summer of 1826, the abundance of these creatures, and of the lady-bird (coccinella septem punctata), was so obvious, as to be remarked by very indifferent persons.

There is a large yellow under-wing moth (phalæna pronuba), too, which is generally abundant. It hides itself during the day in the thickest foliage, and screens itself from the light in the moist grass crops of the mead, where it is perpetually disturbed, and roused from its rest, by the scythe of the mower. That elegant little bird, the yellow wagtail, is a great destroyer of this insect. It is very soon apprized of these movements, and will often attend the steps of the mower, fearless of harm, to watch for its prey. As soon as the moth rises, it is chased; and its exertions and shiftings to escape, and the activity and perseverance of the bird to capture it, are very amusing.

Our lepidopterous insects feed upon various substances in their several states, and most of our butterflies, when perfected, appear to extract the sweet liquor from the tubes or nectaries of plants, and many of our moths obtain their nourishment by similar means: but one butterfly alone, the admirable (v. Atalanta), and at times the peacock (v. Io), feeds upon the juices of our autumnal fruits; and in the months of September and October we may frequently see these beautiful creatures basking and regaling themselves upon the rejected fragments of our wall fruit. They seldom prey upon the growing produce, like the hornet, wasp, and hive bee, but when it has fallen and advanced to a state of fermentation, it becomes the most grateful to them. Nothing can be less injurious than this propensity, and it seems that fruit in such a state is requisite for them by some constitutional formation, as they appear only at the termination of a season when the product of our trees is in a state of great ripeness and decay. The life of this creature appears to be remarkably short, and we have more certain means of ascertaining its duration, than are afforded us for others of the race. It very rarely appears until late in September, and then so perfect and fresh in its plumage as to manifest its recent production from the chrysalis. In some years they abound, and we may see twenty of these beautiful creatures expanding and closing their brilliant wings under the fruit trees on our walls, or basking upon the disk of some autumnal flower; and at another, perhaps, hardly a specimen is to be obtained: nor do they seem like the wasp to be scarce or abundant according to the deficiency or plenty of the season, but influenced by other causes. Many of our butterflies are produced by successive hatches, supplying the places of those which have been destroyed, and hence it is difficult to mark the duration of an individual; and others, as the nettle, peacock and wood tortoise, in many instances survive the winter, hidden in some recess or sheltered apartment, appearing in the spring time-worn and shabby. But van. atalanta appears only in the autumn, not as a preserved creature, but a recent production; and hence we can ascertain the period of its life to be comprised only between those few days that intervene from the end of September to the end of October, by which time its food in our gardens has pretty well disappeared. Some sheltered wall, garnished with the bloom of the ivy, may prolong its being a little longer, but the cold and dampness of the season soon destroy it; rendering the life of this creature, the most beautiful of our lepidopterous tribes, of very brief duration.

The gamma moth (phalæna gamma) is also another creature, that seems in no way affected by moist seasons, which retard the appearance, or apparently destroy so many others of its kind. This creature has imprinted on its dark wings a white character, something like the letter Y, but more like the small Greek gamma, and hence has received a pertinent name. Like Cain, it bears with it, in all its wanderings, a mark that distinguishes it from others of its race. Its habits also are quite unlike those of other moths, as it feeds principally in the day- time; and we see it late in the summer whisking about with all the activity and action of the hummingbird sphinx. Like the latter it keeps its wings, while feeding, in a constant state of vibration; haunts clover-fields, and the yellow blossoms of the wild mustard, and the heads of the pasture scabious. It seems little mindful of the common frosts of October, retiring from us with such reluctance, that, should the autumn be fine, we not uncommonly find it in some piece of aftergrass, enjoying there the few flowers which linger out the approaches of November.

In the autumn of the year 1827, the larvæ of the goat moth (phalæna cossus) abounded beyond any customary proportion, and we could commonly see the traces made by these creatures in the dust. They had apparently fed during the summer in the earth, and were now proceeding in search of a retreat during winter to some old hedge-row tree, a part to repose, and those which approached maturity, to abrade the softer wood, and form their cases, preparatory to changing to a final perfect state in the spring. At times we observed them coursing along our paths with great strength and activity; and when not seen, that peculiar subtle smell, which proceeds from them, and has been thought to resemble that of the goat, was perceptible in all our walks. The object and seat of this odor seem not well understood. Some have conjectured it to proceed from a fluid evacuated from the mouth, and discharged to soften the wood in which they burrow. But it seems inconsistent with any probability, that this creature, which is furnished with such very powerful mandibles, should be gifted with an auxiliary aid to accomplish its object; while of the many insects that perforate timber, most of them with inferior means, no other possesses an equivalent agent to facilitate its labors; for not one of them, as far as we know, is so supplied. Besides, if such were the purpose, the discharge would be made only when required, and thus this unpleasant odor not always perceptible. The microscope too does not manifest the exudation of any fluid. The larva is furnished with eight curious retractile processes on its under side, in the manner of what entomologists call the “prolegs.” These are encircled with little hooks, made use of probably to remove the fragments of the wood, when broken off by the mandibles above, and clear the passages. The strength of these jaws is so great, that they will very soon destroy any common chip box in which the animal may be placed, by abrading the edges, to effect its escape. With us they chiefly inhabit the ash; and we very commonly see at the roots of our aged trees the fragments removed by them in forming their passages. In breaking up the decayed pollards, we not unusually find the grub in all the stages of its growth; but more generally observe them without inhabitants, yet perforated with paths large enough to admit the finger. I suspect that these “augerworms” are the primary cause of the decay of the tree; having often observed their perforations, and found them, both large and small, in the solid spur or root of the tree, when the upper portion, having been bored and in a state of decline, is abandoned by them. Those that are full fed appear to form their cases in that part which has lost coherency, while the younger and imperfected creatures mine their way, and obtain nutriment in the solid timber, thus killing the tree by inches; when rain and moisture find lodgment, and complete the dissolution. One year’s preparation is the period usually assigned to the larvæ of most insects, before they arrive at their perfect state; but by the goat moth three years are required before it attains its winged state from the egg. Consequently, for the larger portion of its life it is occupied in these destructive operations; and thus this creature becomes a very powerful agent in reducing these Titans of the vegetable world, crumbling them away to their original dust: for what was decreed to be the termination and punishment of man is found in active operation throughout the whole chain of nature’s works, which are but dust, and unto dust return, continuing an endless series of production and decay, of restoration and of change. All these larvæ which I have observed in the colder portions of our year, were hard, stiff, and torpid, but soon became relaxed and animated by the warmth of the hand: thus they probably remain quiet during the winter months, but revive in spring, and recommence their ravage in the tree. The caterpillar of this moth I believe to be the largest of any of those of the British lepidopteræ; and when full fed exceeds in size that of the death’s-head sphinx. To those who dislike the appearance of things of this nature, it is particularly disgusting; not only from its magnitude and smell, but from its color, which is a lurid red, so compounded with a dingy yellow, as to give it a lividness of look, conveying the idea of something raw. Common as the grub is in some years, I have seldom been able to obtain the moth, without the often tedious process of feeding the larvæ, and waiting for its change.

Of those caterpillars which feed upon the foliage of vegetation, a considerable portion are picked off and consumed by the numerous little birds which are constantly hunting after them, as food for themselves or their young ones; and many of those which are supported by the roots of plants, and remain covered in the soil, are detected by the perception of rooks, and birds of that order; but those which feed upon the internal parts of trees seem exempted from any of these causes of destruction. This is possibly a reason that the larvæ of phalæna cossus is so plentifully found; but yet it is pretty certain that some other and equally fatal visitation assails them, and reduces their numbers during the long period which is required to perfect their state: for though, by feeding and care, (for they are very impatient of confinement,) we can obtain the moth in numbers, yet few seem to survive and become perfected by the common processes of nature, at least I have seldom found them in this state, though the larvæ is so plentifully seen.

The designs of supreme intelligence in the creation and preservation of the insect world, and the regulations and appointments whereby their increase or decrease is maintained, and periodical appearance prescribed, are among the most perplexing considerations of natural history. That insects are kept in reserve for stated seasons of action, we know, being commonly made the agents of Providence in his visitations of mankind. The locust, the caterpillar, the palmer-worm, the various family of blights, that poison in the spring all the promise of the year, are insects. Mildew, indeed, is a vegetable; but the wireworm destroys the root, the thrips the germ of the wheat, and hunger and famine ensue. Many of the coleopteræ remove nuisances, others again encumbrances, and worms manure the soil; but these are trite and isolated cases in the profusion of the animal world; and, left alone, as we are, in the desert of mere reason and conjecture, there is no probability that much satisfactory elucidation will be obtained. They are not perhaps important objects of inquiry; but when we see the extraordinary care and attention that has been bestowed upon this part of creation, our astonishment is excited, and forces into action that inherent desire in our minds to seek into hidden things. In some calm summer’s evening ramble, we see the air filled with sportive animated beings: the leaf, the branch, the bark of the tree, every mossy bank, the pool, the ditch, all teeming with animated life, with a profusion, an endless variety of existence; each creature pursuing its own separate purpose in a settled course of action, admitting of no deviation or substitution, to accomplish or promote some ordained object. Some appear occupied in seeking for the most appropriate stations for their own necessities, and exerting stratagems and wiles to secure the lives of themselves or their offspring against natural or possible injuries, with a forethought equivalent or superior to reason; the aim in some others we can little perceive, or, should some flash of light spring up, and give us a momentary glimpse of nature’s hidden ways, immediate darkness closes round, and renders our ignorance more manifest. We see a wonderfully fabricated creature struggling from the cradle of its being, just perfected by the elaboration of months or years, and decorated with a vest of glorious splendor; it spreads its wings to the light of heaven, and becomes the next moment, perhaps, with all its marvellous construction, instinct, and splendor, the prey of some wandering bird! and human wisdom and conjecture are humbled to the dust. That these events are ordinations of supreme intelligence, for wise and good purposes, we are convinced; but are blind, beyond thought, as to secondary causes; and admiration, that pure source of intellectual pleasure, is almost alone permitted to us. If we attempt to proceed beyond this, we are generally lost in the mystery with which the divine Architect has thought fit to surround his works; and perhaps our very aspirations after knowledge increase in us a sense of our ignorance: every deep investigator into the works of nature can scarcely possess other than an humble mind.

In all our pursuits we shall find in nature, wheresoever we can penetrate, a formation, a faculty adapted to all the wants and comforts of the creature, yet the objects of infinite wisdom in the creation of this world of matter, animate and inanimate, will probably never be made known to mankind; for though knowledge is in a constant progressive state, and the attainments of science in latter years have been comparatively prodigious, yet these acquirements are in fact but entanglements: they lead us deeper into surprise and perplexity, and the little perceptions of light which we obtain serve to show how hopeless any attempt must be to penetrate the secrets of infinity, a conviction, if we “dwell deep in the valley of humility,” that will in no manner discourage our pursuits, but rather incite our ardor to investigate so exhaustless a store, which will lead us, from contemplation, to admiration, to devotion.

That pretty sparkler of our summer evenings, so often made the plowboy’s prize, the only brilliant that glitters in the rustic’s hat, the glow- worm[60] (lampyris noctiluca), is not found in such numbers with us, as in many other places, where these signal tapers glimmer upon every grassy bank; yet, in some seasons, we have a reasonable sprinkling of them. Every body probably knows, that the male glow-worm is a winged, erratic animal, yet may not have seen him. He has ever been a scarce creature to me, meeting perhaps with one or two in a year; and, when found, always a subject of admiration. Most creatures have their eyes so placed as to be enabled to see about them; or, as Hook says of the house fly, to be “circumspect animals;” but this male glow-worm has a contrivance by which any upward or side vision is prevented. Viewed when at rest, no portion of his eyes is visible, but the head is margined with a horny band, or plate, being a character of one of the genera of the order coleoptera, under which the eyes are situate. This prevents all upward vision; and blinds, or winkers, are so fixed at the sides of his eyes as greatly to impede the view of all lateral objects. The chief end of this creature in his nightly peregrinations is to seek his mate, always beneath him on the earth; and hence this apparatus appears designed to facilitate his search, confining his view entirely to what is before or below him. The first serves to direct his flight, the other presents the object of his pursuit: and as we commonly, and with advantage, place our hand over the brow, to obstruct the rays of light falling from above, which enables us to see clearer an object on the ground, so must the projecting hood of this creature converge the visual rays to a point beneath. This is a very curious provision for the purposes of the insect, if my conception of its design be reasonable. Possibly the same ideas may have been brought forward by others; but, as I have not seen them, I am not guilty of any undue appropriation, and no injury can be done to the cause I wish to promote, by detailing again such beautiful and admirable contrivances.