The Life of an Insect

he larva did, or not? On a careful examination we might detect, with the help of a magnifying glass, the same breathing holes or spiracles, spoken of on page 1

racles, of the pupa, and has represented them in an engraving, of which a copy is furnished at page 161. He found that they are protected by little valve-like contrivances, just as our mouths are protected by our lips; and these can be opened or closed at pleasure by the creature;

spiracles are situated, thus clearly proving that the creature breathes air by this apparatus. The fact may be tested also in another way-and both this and the preceding experiment are due to the ingenious Réaumur. He took the pupa of a butterfly, and suspending it by a thread immersed it half way down in oil; on taking it out after some time it was still alive and apparently uninjured, the reason being, that the entire number of its breathing-holes were not covered. He took another of the same species, and plunged it entirely under the oil, and taking it out after a ti

lives in the water, but whose pupa is an air-breathing creature, and consequently would perish if the change from larva to pupa were to take place under water, without some especial

any other change in their appearance than that they had grown to a considerable size. But at the commencement of this month I noticed that they became very uneasy; they forsook their leaves, and wandered about the sides of the boxes, which contained water. Sometimes they would creep out of the water, and again would go into it. They seemed as if they were in search of something which they had lost. It was now evident that their object was to find some convenient place in which to undergo their transformation into pup?, but they did not like the boxes in which they were confined, and several even di

water. By means of several silken cords the insect fastens together two, and sometimes even three leaves, between which it spins an oval cocoon, composed of very white silk. This cocoon is of a double structure; the true inner cocoon, which is very white, is placed within an outer envelope of silk, of a greyish or br

between which the Worm lies, th

y, water. De Geer states that he did not find a particle of water in all the cocoons which he opened. In order to ascertain whether or not it was really necessary for the pupa to be thus carefully housed in a silken ball full of air beneath the water, he too

perfect

eath was the evaporation of their fluids, which of course does not take place when they are enshrouded in their cocoons, and surrounded on all sides with water. He made one more experiment with them, which was as follows:-He took several out of their cocoons, and placed them in water in such a manner, that one of thei

; and a number of men must labour hard to stop up the chinks, where the water comes pouring in. Thus men, and machines of great power, and in sufficient number, are requisite to enable the most expert engineer to form a cavity at the bottom of the river's bed. What if we were to give him as a problem, to build a cell which should be perfectly water-tight and filled with air, without allowing him to employ any of these means, and to insist that it should all be done withou

era, showing its

dle in the summer. Many of these are the pup? of various species of gnats; and when we watch them come darting upwards by a succession of flaps with their tail, until they reach the surface, where they remain for a short time, we see the means by which, although they live immersed in water, they are enabled to breathe the air. For if we scrutinized them a little narrowly, we might detect on each side of their largest extremity or head, a pair of minu

he necessities of their case. They are plunged some way down in the water, and air is conveyed to them by a hollow tail-like tube, which is always found to open on the surface of the water. It is a curious thing to contemplate these little creatures, so beautifully provided for in this manner. Secure of all they need in the supplies of air furnished to them by their tube, they rest peacefully i