got into this position for an instant, when, by swelling the part of its body above water, the skin cracks between the two breathing tubes, and immediately the head of the gnat makes its appearance through

no rough treatment can upset or sink; it being doubtless essential for the welfare of the future progeny that the eggs should float on the surface of the water, and not sink in it.

The two next stages of the gnat's existence are passed in the water. Every one is well acquainted with the little active wriggling creatures, with large heads, which during the summer months abound in water, and especially rain-water, when freely exposed to the air. These are the larvæ and pupæ of gnats. The larvæ, as soon as they leave the floating egg, descend into the water, there to await the arrival of the period for assuming their winged aërial condition. But although they thus exist in a different element, yet the respiration of atmospheric air is absolutely necessary to their existence; and the means of obtaining it are accordingly provided in the shape of a curious apparatus situated near the tail of the larva. The larva suspends itself from the surface of the water by means of the extremity of this breathing tube, which is capable of being opened out into a stellate form, and it thus, while used as an organ of respiration, also acts as a buoy. When the little creature wishes to descend, it closes the hairs at the end of the tube; and on reäscending they are again opened.

After two or three moultings, the larva of the gnat becomes a pupa; in this state food seems to be no longer necessary, but fresh air is indispensable to its existence, though still living in the water. Unlike that of the larva, the respiratory apparatus of the pupa consists of two tubes placed behind the head, instead of being situated in the tail, which in the pupa is fin-shaped, and appears by its motion to assist the animal in maintaining its position at the surface of the water.

The next operation that of assuming the perfect state-is a most interesting one, which we have witnessed with admiration many times. It is well described in Rennie's "Insect Transformations;" and this account being very accurate, we give it entire.

About eight or ten days after the larva of a gnat is transformed into a pupa, it prepares, generally towards noon, for emerging into the air, raising itself up to the surface so as to elevate its shoulders just above the level of the water. It has scarcely

the rent. The shoulders instantly follow, enlarging the breach so as to render the extrication of the body comparatively easy. The most important, and, indeed, indispensable, part of the mechanism, is the maintaining of its upright position, so as not

"When

prevent it from flying. Its chief support is the rugosity of the envelop which it is throwing off, and which now serves it as a life-boat, till it gets its wings set at liberty, and trimmed for flight. The body of the insect serves this little boat for a mast, which is raised in a manner similar to movable masts in lighters constructed for passing under a bridge, with this difference, that the gnat raises its body in an upright direction from the first. the naturalist," says Réaumur, "observes how deep the prow of the tiny boat dips into the water, he becomes anxious for the fate of the little mariner, particularly if a breeze ripples the surface, for the least agitation of the air will waft it rapidly along, since its body performs the duty of a sail as well as of a mast; but as it bears a much greater proportion to the little bark than the largest sail does to a ship, it appears in great danger of being upset; and once laid on its side, all is over. I have sometimes seen the surface of the water covered with the bodies of gnats which had perished in this way; but for the most part all terminates favorably, and the danger is instantly over." When the gnat has extricated itself all but the tail, it first stretches out its two fore legs, and then the middle pair, bending them down to feel for the water, upon which it is able to walk as upon dry land, the only aquatic faculty which it retains after having winged its way above the element where it spent the first stages of its existence.-(Lib. Ent. Knowl. Ins. Trans., p. 317.)

The dragon-flies, or "horse-stingers," as they are erroneously called by the country people, also deposit their eggs in the water, where they are hatched; and the young, like those of the gnat, pass the two first stages of their life in that element. The larva is furnished with a very curious respiratory apparatus, by which it is enabled to sustain an intermittent pumping up and discharge of water, thus serving at the same time both as an organ of locomotion and of respiration. But this is not the only curious circumstance connected with this larva. The under lip of the mouth in the larva of most insects is very small; but in that of the dragon-fly it is very large and of a most extraordinary structure, thus well described by Kirby and Spence :

It is

high as the nose, concealing not only the chin and the first-mentioned elongation, but the mouth and part of the cheeks; conceive, moreover, that to the end of this last-mentioned plate are fixed two other convex ones, so broad as to cover the whole nose and temples-that these can open at pleasure transversely, like a pair of jaws, so as to expose the nose and mouth, and that their inner edges where they meet are cut into numerous sharp teeth, or spines, or armed with one or more long sharp claws;-you will then have as accurate an idea as my powers of description can give of the strange conformation of the under lip in the larvæ of LibelJulina, which conceals the mouth and face precisely as I have supposed a similar construction of your lip would do yours. You will, probably, admit that your own visage would present an appearance not very engaging while concealed by such a mask; but it would strike still more awe into the spectators, were they to see you first open the two upper

jaw-plates, which would project from each temple like the blinders of a horse; and next, having by means of the joint at the chin, let down the whole apparatus, and uncovered your face, employ them in seizing any food that presented itself, and conveying it to your mouth. Yet this procedure is that adopted by the larva of the dragon-fly provided with this strange organ. While it is at rest, it applies close to and covers the face. When the insects would make use of it, they unfold it like an arm, catch the prey at which they aim by means of the mandibuli-form plates, and then partly refold it so as to hold the prey to the mouth in a convenient position for the operation of the two pair of jaws with which they are provided. Réaumur once found one of them thus holding and devouring a large tadpole; a sufficient proof that Swanmerdam was greatly deceived in imagining earth to be the food of animals so tremendously armed and fitted for carnivorous purposes. In the larvæ of Libellula, Fabr., it is so exactly resembling a mask, that if entomologists ever went to masquerades, they could not more effectually relieve the insipidity of such amusements, and attract the attention of the demoiselles, than by appearing at the supper table with a mask of this construction, and serving themselves by its assistance.-(Introd., iii. 126.)

These voracious larvæ do not, however, trust solely to this curious apparatus when seeking for prey, for they stealthily close upon it as a cat will do upon a bird or upon a mouse, and then suddenly unmasking seize it by surprise; insects, tadpoles, and even small fishes are thus captured. Like the pupa of the gnat, that of the dragonfly is under the necessity of seeking the air in order to assume its perfect winged condition, but its avoidance of water is much more complete than in the case of the gnat; for, not content with merely ascending to the surface, there to get rid of its now useless integument, the dragon-fly leaves the water entirely, generally by crawling up the stems of aquatic plants, upon which it fixes itself by means of its claws, and thus remains motionless for a time, as if to gain strength for the coming struggle. After a while, the envelope may be seen to burst open between the shoulders; through the aperture protrudes the head of the perfect fly, and this is quickly followed by its legs, the cases of which remain attached as before to

the plant. Another period of rest now intervenes, the head and upper portion of the body being bent backwards, and gradually becoming dry and firm. The fly then, firmly grasping the upper portion of its cast skin with its feet, gradually draws out the remainder of its body, and again rests immovably. During this state of inaction the wings expand, all the crumples, plaits, and folds incidental to the confined space previously occupied gradually disappear, and the whole wing becomes a beautiful smooth gauzy membrane, traversed by nerves, and nearly the length of the body, which has at the same time been gradually enlarging and lengthening, and the limbs acquiring their just size and proportions. Moreover, while the wings are thus drying and expanding, the insect is instinctively careful to prevent their coming in contact, while wet, with any part of the body, which would render them unfit for use, by arching the latter in such a way that the convexity is downwards. The whole of this curious process we have watched with admiration; and once had the pleasure of explaining it to a little intelligent country boy, who happened to pass the piece of water where it was going on, and put the question, "What be them

'ere things a-doin?"

The

In a former number of this "Review" we quoted from the "Zoologist" an exceedingly interesting account of the final transformation of a small species of ephemera, or day-fly, illustrative of what Mr. Newman well calls "the strange fact of an insect's flying before it reaches the imago; that is, flying in its penultimate state." eggs of these flies are laid in the water, like those of the dragon-flies, which belong to the same class (Neuroptera,) and the gnats. The larvæ live in the water two and even three years; when the imago is about to cast off its pupa-skin, it leaves the water, and proceeds in the manner described in the quotation above referred to. The duration of the perfect insect's life is at most a few hours.

The phryganeæ, or caddis-flies, also deposit their eggs in the water. The larvæ construct for themselves little habitations of small shells, (which sometimes contain their living tenants,) grains of sand, small stones, bits of stick, and other similar substances, made to adhere by the prototype of marine glue. These larvæ cannot swim, but, being furnished with six legs, they walk with facility at the bottom of the water; and being themselves heavier than water, it is necessary that their habitations should have a specific gravity so nearly corresponding with that of water, that the animals may move about without being floated to the surface on the one hand, or compelled to remain at the bottom on the other. The larvæ, therefore, evince their instinct-prompted knowledge of hydrostatics, by attaching to their cells a piece of straw, or some other light substance, if too heavy; or if too light, a shell or piece of gravel. They never quit their habitations until about to assume the perfect form; when about to become pupæ, the larvæ withdraw within their cases, after fixing them to some solid substance, and close each extremity with

a grating which readily permits the passage of water through the case, this being necessary for respiration. The pupa makes its way out by means of a pair of hooked jaws, and swims about until it leaves the water for the purpose of undergoing its final ecdysis; some of them climb up aquatic plants, like the pupe of dragon-flies; others simply float up to the surface, as the pupæ of the guats do.

It is very difficult, without actually witnessing the successive stages of the lives of such insects, to realize the curious fact, that the little merry dancing gnats, whose aerial gambols all have observed; and the quick-darting dragon-flies, with their iridescent glistening wings; and the gay ephemeræ, whose aërial life is to terminate in a few hours from the period of their assuming it; were once the inhabitants of an element which would be fatal to them in their now perfect form. Yet are there many insects whose lives are passed under similarly opposite conditions; and still more numerous are those whose progress from birth to maturity is characterized by changes of structure

so loosen the turf, that it will roll up as if cut with a turfing spade." Records have from time to time appeared of the extensive ravages of these grubs, which do not confine themselves to grass, but also eat the roots of corn. The rooks are their most deterinined enemies; for they not only follow the plough for the purpose of devouring the grubs of the cockchafer, which, among others, are sometimes turned up in the furrows in great numbers, but they instinctively, as it were, pitch upon those meadows and portions of meadows where the grubs are pursuing their subterranean work of destruction, root up the grasses with their strong beaks, and feast luxuriously upon the rich repast thus laid bare; as if to revenge themselves upon the cause of the charge undeservedly brought against them, of doing an injury to the farmer by uprooting his grass, when, in reality, they are conferring upon him one of the greatest benefits, by destroying an insidious enemy.

The very extensive class Coleoptera, or the beetle tribe, to which the cockchafer belongs, furnishes many other examples of insects exceeding

they are most familiar with it-that of a large beetle-is the ultimate one of four several stages of insect life. Four years before the May-bug makes its presence unpleasantly known to us by dashing in our faces during our rural walks on the delicious evenings we sometimes have in May, it was carefully deposited in some field or meadow, in the form of an egg, in company with perhaps hundreds of similar eggs, by a May-bug like itself. The parent, having performed this duty, would soon cease to exist; and towards autumn the eggs would give birth to numerous minute whitish grubs. Between this period of hatching and the third autumn, the grubs increase greatly in size, and cast their skins three or four times, each time burrowing deeper than their usual feeding level, as they likewise do in winter, when they become torpid. In the third autumn after they are hatched the grubs prepare for assuming the pupa state, by burrowing to the depth of about a yard; and in a little chamber at the bottom of the burrows they remain inactive until the following January or February, when the perfect beetles emerge from the last covering they are to cast off; but for ten or twelve days they remain quite as soft as when in their first stage of existence, and do not venture to quit their subterranean asylum until May, when they may be seen crawling out of the ground in great numbers, and soon taking flight. In the perfect state these insects live upon the leaves of trees; but the voracious grubs devour the roots of grasses, sometimes destroying whole acres of the finest pasture, and, as Kirby and Spence well observe, they "undermine the richest meadows, and

whose habits in their various stages would probably suggest remedies for the injuries inflicted by them. On the other hand, the same class furnishes examples of insects conferring benefits upon man, either by preying upon other insects whose ravages interfere with his comforts or with the supplying of his necessities, or by removing decaying substances which would otherwise become offensive to the senses. Of the former description are the larvæ of the lady-birds, which do good service by destroying the Aphides infesting the hop; of the latter, in a small way, is the sexton, or burying-beetle, which actually consigns to the bosom of mother earth the body of any small animal it may meet with; not, however, with a view of conferring a benefit upon the "lord of creation," but in order that its own progeny may be provided with a fitting nidus, and that they may find a sufficient store of provision on emerging from the egg. An exceedingly pleasing description of the proceedings of this beetle and his mate, from the pen of an observer who, we regret, now writes no more, appeared some years ago in the Entomological Magazine," with the signature of "Rusticus, of Godalming," and is quoted by Mr. Newman in his "Introduction to the History of Insects," from which we here extract it.

The sexton-beetle is about an inch in length; it is of a black color, and so fœtid, that the hands smell for hours after handling it; and if it crawl on woollen clothes which are not washed, the smell continues for several days. The sextonbeetle lays its eggs in the bodies of putrefying

sect tribes do but hasten its fulfilment, while engaged in destroying our books, our furniture, the wooden frame-work of our houses, or the lofty tenants of our forests. The ease with which wood, when much "worm-eaten," is crumbled, even between the fingers, is well known: but it may not be so generally understood that the "worms" which produce this effect upon articles of furniture formed of wood, are no other than the soft-bodied grubs of various coleopterous insects, which are thus carrying out on a small scale the more extensive operations that quickly reduce to a similar condition the giants of tropical forests. Our domestic pests of this description are chiefly small beetles, which pass the early part of their lives in the wood, and by means of their powerful jaws mine through it in all directions, only emerging when they assume the perfect state. One of these is the "death-watch," which even yet is an object of superstitious dread to the inhabitants of many an old house, of the wood-work of which it has taken possession. The ticking noise, so alarming to weak minds, and which is often considered an infallible presage of impending death to some member of the family, is merely the call-note of the perfect beetle of several species chiefly belonging to the genus Anobium, and, as we have often observed, principally by the largest species, A. tesselatum. The man

The omen is broken, the danger is over,
The maggot will die, and the sick will recover.

After enumerating many important services rendered to man by insects in the removing of decaying organic matters, Kirby and Spence conclude their long list of insect injuries and benefits with the following paragraph:

Benefits equally great are rendered by the wooddestroying insects. We, indeed, in this country, who find use for ten times more timber than we produce, could dispense with their services; but to estimate them at their proper value, as affecting the great system of nature, we should transport ourselves to tropical climes, or to those under the temperate zones, where millions of acres are covered by one interminable forest. How is it that these untrodden regions, where thousands of their giant inhabitants fall victims to the slow ravages of time, or the more sudden operations of lightning and hurricanes, should yet exhibit none of those scenes of ruin and desolation that might have been expected,

but are always found with the verdant characters of youth and beauty? It is to the insect world that this great charge of keeping the habitations of the Dryads in perpetual freshness has been committed. A century almost would elapse before the removal from the face of nature of the mighty ruins of one of the hard-wooded tropical trees, by the mere influence of the elements. But how speedy its decomposition, when their operations are assisted by insects! As soon as a tree is fallen, one tribe attack its bark, which is often the most indestructi

bles the ticking of a watch, is thus very accurately described by Kirby and Spence.

Raising itself upon its hind legs, with the body somewhat inclined, it beats its head with great force and agility upon the plane of position; and its strokes are so powerful, as to make a considerable impression if they fall upon any substance softer than wood. The general number of distinct strokes in succession is from seven to nine or eleven. They follow each other quickly, and are repeated at uncertain intervals. In old houses, where these insects abound, they may be heard in warm weather during the day. The noise exactly resembles that produced by tapping moderately with the nail upon the table; and when familiarized, the insects will answer very readily the tap of the nail. (Introd., ii. 383.)

They also answer the ticking of a watch, if laid upon wood inhabited by them. By way of relieving this dry discussion, we may quote Dean Swift's description of the death-watch, with his infallible method of breaking the spell. He calls

it

solid trunk are bored by others. The rain thus insinuates itself into every part, and the action of heat promotes the decomposition. Various fungi now take possession and assist in the process, which is followed up by the incessant attacks of other insects, that feed only upon wood in an incipient state of decay. And thus, in a few months, a mighty mass, which seemed inferior in hardness only to iron, is mouldered into dust, and its place occupied by younger trees full of life and vigor.(Introd., i. 260.)

That the office of clearing the ground encumbered by the fallen monarchs of the forest is effectually aided by insects, is well attested by travellers in those regions where vegetation assumes its most luxuriant character; and in this work the larvæ of the beetle tribe do good service, in which they are assisted by those of insects belonging to the tribe next to be considered.

The Lepidoptera, or the butterfly and moth tribe, offers, perhaps, some of the most attractive insects, whether to the scientific or the non-scientific entomologist. The butterfly, with its gorgeous hues,

its devious flight, and the comparative obscurity of its previous life, has furnished to poets of all ages some of their most glowing similes, and to philosophers, from a very early date, a number of striking and beautiful analogies with the repose of the tomb and the probability of a more glorious hereafter. These insects are also associated with the most agreeable images of the happiest period of our early days, when, like the youthful Marcius, as portrayed by Shakspeare, we pursued the "rainbow butterflies," regardless of wet, dirt, and tumbles, and equally careless as to whether the object