the bottom, where they are speedily hatched. The larva is a somewhat uncouth, broad, and flat, olive-coloured animal, rather spider-like, having six sprawling legs, which crawls about the mud at the bottom of ponds, or glides by a singular mechanism through their waters. The hinder extremity of the body is furnished with several leaf-like processes, capable of being brought closer together, or opened at pleasure. These close the orifice of a

When the Insect

cavity, whose sides are very muscular. wishes to move rapidly, it opens this cavity, which thus becomes filled with water; then, by a contraction of the walls of the cavity, the water is forcibly ejected in a stream as from a syringe; and, by the re-action produced by the impact of the jet d'eau upon the surrounding fluid, the creature shoots ahead, with its legs closely packed along its sides.

But the most singular part of its structure is its face. "Conceive," says the graphic and eloquent Kirby, "your under lip to be bony instead of fleshy, and to be elongated downwards, so as to wrap over your chin, and extend to its bottom; that this elongation is then expanded into a triangular convex plate, attached to it by a joint, so as to bend upwards again, and fold over the face as high as the nose, concealing, not only the chin and the first-mentioned elongation, but also the mouth and part of the cheeks: conceive, moreover, that to the end of the 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, and spines, or armed with one or more long and 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 of the larva of the tribes of Libellulina (Dragon-flies), which conceal the mouth and face precisely as I have supposed a similar construction of your lips 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-like plates, which would project from your temples like the blinders of a horse; and next, having, by means of the joint at your 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."

Such is the larva, from which the pupa does not differ in any respect, except that the rudiments of the future wings are seen budding out from the thorax. It is no less active, no less fierce, no less voracious than the larva. When the time of its transformation approaches, it crawls out of the water up some aquatic plant, or on a twig upon the bank, where it remains a while for the skin to dry. Presently, a crack appears down the back, and the fly begins to emerge, as represented in the lower left-hand figure of the accompanying engraving. As soon as the feet are free, it invariably bends backward, and hangs with its head downward, as if exhausted, for some minutes. Then it rears itself up, catches hold of the twig with its hooked feet, and draws the extremity of its body out of the pupa-case, leaving the latter firmly fixed by its own

feet to the support. The wings are minute, soft, and dense, but they soon expand (as described in the case of the

Transformations of Dragon-fly.

Butterfly), and acquire the firmness, transparency, and gloss which are so admirable in the perfect Insect.

CHAPTER XVIII.

INSECTA (Insects).

Continued.

In Insects we perhaps reach the highest point of comparative perfection among invertebrate animals, whether we regard the condensation of their organs, the solidity of their skeleton, the consequent vigour and precision of their movements, the concentration of their nervous system, or the manifold intelligence which they display. That wonderful adaptation of means to ends, which, so often recurring as we study the instructive actions of animals, calls forth more than anything else our recognition and praise of an all-wise Creator, is nowhere more conspicuous than in Insects; and is pre-eminently seen in what have been felicitously termed the architectural habits of such species as prepare habitations for themselves, or protections for their offspring.

Most of our readers are familiar with that exquisite solution of a geometrical problem*-the honeycomb.

* Réaumur, the eminent French entomologist, proposed to M. König, one of the ablest mathematicians of his day, the following problem :-" Amongst all possible forms of hexagonal cells, having a pyramidal base composed of three similar and equal rhombs, to determine that which could be constructed with the least expenditure of material." The mathematician undertook the solu

They have learned that the industrious Bees, impelled by nature to live in society, combine to form a common structure of cells, for the reception of the eggs and young, which are to form the future commonwealth, and the store of food which is necessary for their nutrition. This work is to be formed out of wax-a substance that does not exist as yet, but which is to be elaborated by a natural chemistry from the bodies of the Bees themselves. The cells are perfect hexagons, divided from each other by the thinnest possible walls that the material will sustain, and built in double series, the bottom-point of one being the point between the bases of three others, which open in the opposite direction. Now, it is found by observation, that the walls are not built up in those thin plates, which we see them to be when perfected; but, on the contrary, that the wax is laid down in rounded knobs, out of which the cells are then excavated by the jaws of the workers, each one knowing exactly, by her wondrous. instinct, how much may be pared away, without breaking into the domains of her fellow-artificers, who are similarly excavating on every side of her.

But the labours of the Hive-Bee, though truly admir

tion of this very beautiful theorem, and at last demonstrated that, among all kinds of cells with pyramidal bases, that would require the least quantity of material which should have its base composed of three rhombs, the angles of which should measure respectively 109° 26′ and 70° 34'. M. Maraldi, another eminent naturalist, had in the meanwhile calculated, with as much accuracy as he was able, the real angles met with in the cell of the Bee, which he had estimated, the former at 109° 28', the latter at 70° 32', leaving only two minutes of difference between the calculation and the result of measurement; and more recent researches, conducted with the delicate instruments of modern science, have shewn even that slight discrepancy to be erroneous, and proved that the figures pointed out by mathematical research, and those adopted by the insectlabourer, are precisely identical.-Jones's "Nat. Hist. of Anim.," ii. 235.)