they recover their strength and do not appear to have been incommoded.

But what deferves our particular attention is, that thefe minute creatures, though air is fo neceffary to them in fummer, live during the winter with very little refpiration if any at all. They are then in a fort of fleep or lethargy, in a, ftate between life and death. The falt and the vifcid humour which tranfpire from their bodies grow hard by the cold, and form a fpecies of cruft around them. In this ftate the pores of their bodies are contracted and in a manner shut the vital spirits are concentrated in the interior parts of the infect, and they lofe nothing of them by tranfpiration. As they make no motion, nothing is diffipated they remain always in the fame ftate, and have no occafion to refpire in order to acquire new ftrength.

We cannot fufficiently admire the goodness of the Creator in providing for the wants of his creatures. If air is neceffary for their existence, he gives it to them. The quality and quantity of this cannot be the fame for all animals; he gives to each the organs neceffary for inhaling juft what is fufficient for them, and the kind that fuits them. He weighs and deftributes it to them as it were by measure. Men enjoy this precious gift in the fame way with infects; but how few are there who bave given themfelves the trouble of reflecting on a benefit without which it would be impoffible to live. How have they requited Him for it? From our birth we have breathed, the air is common to all animals, and they enjoy it without labour or expence; and therefore instead of being grateful, men become, infenfible to fo precious a gift. As each infpiration and each expiration are fo many authentic teftimonies of the power, of the wifdom and the goodnefs of God, there is not a

moment

moment of our lives which does not invite us to celebrate his perfections and to exprefs our own gratitude. The Pfalmift was penetrated with the juftice of this reflection. "Let every thing that hat. breath fays he, praise the Lord."

PSALM CL. 6.

CHAP. VI.

OF THE GENERATION OF INSECTS.

WHEN a living creature produces another of the fame fpecies with itself, we fay that it has engendered it. All generation is preceded by an intercourfe between the male and the female. This is a general rule from which infects are not excepted; the only difference to be remarked with regard to them is, that the way in which the male infects couple with the females is different in different fpecies. However, this commerce fecundates the female and puts her in a condition to lay her eggs when the feafon has arrived. The Ephemera is fingular in this point; for it is only after the female has depofited her eggs on the furface of the water that the male fecundates them.

The variety among the eggs of infects is incredible: it may be faid to equal the number of fpecies. Without confidering the difference in their fize, I shall only remark the moft ftriking diversities among them whether from their figure or colours. The moft common figures are the round, the oval, and the conic; but it must be attended to that there are fome more and fome lefs fo, and that fome approach more. to these figures than others. As to colours the difference

H

ference is more ftriking. Some like thofe of fome fpiders have the fplendor of little pearls; others like thofe of the filk worm are yellow and of the colour of a grain of millet. Others are of the colour of fulphur, of gold, or of wood. Laftly there are fome green and brown, and among thefe laft there are various tinges of brown, fuch as yellowish brown, reddish brown, chefnut, &c.

The matter which thefe eggs contain is at first a liquid fubftance, and afterwards forms the infect, which is very artfully enclofed in the fhell. There it remains till the fuperabundant humidity is diffipated, and its members have acquired ftrength enough to break the egg, when it comes out. At this period it makes a hole in the fhell raifes up the little broken pieces, ftretches forward the head, which hitherto had been bent in towards the belly; difplays its antennæ, and puts them in motion; brings out its legs one pair after another, attaching itself with the first pair to the egg, till the whole body is drawn out.

All infects do not remain equally long in the egg, A few hours is fufficient for fome, while it requires many days, and even many months before others break their prifon. Eggs, which during winter have been in a warm place, foon lofe their humidity and are hatched prematurely. It is worthy of remark, and must not be forgotten, that thofe caterpillars which live on green vegetables, never leave their eggs till the herbs and leaves they feed on are fufficiently advanced. Providence has been careful to provide for their neceffities, and to infure them of food the moment they want it.

Another circumftance not lefs remarkable, is that many of thefe eggs, notwithstanding their minutenefs and delicacy are able to refift both cold and wet which do not deftroy them. But even though num

bers of them fhould be destroyed, that lofs would be eafily repaired by the fertility of the females. One infect generally lays a great number of eggs; from thirty to fixty and even fome hundreds. This I learnt by the following circumftance. On the 6th of June 1736, a forefter brought me a butterfly, the upper wings of which were dark, fpotted with eight white fpots, and the under wings orange coloured. I fixed it with a pin to a board, and on the afternoon of the fame day, found that it had laid four hundred and thirty one eggs of the fize of a grain of millet, which refembled fmall pearls. At firft they were foft, as I eafily perceived because they were flat on that fide which rested on the board, and refembled the top of • a loaf. Their figure cannot be observed while they lie one upon another; they must be detached to have a diftinct view of them. In ten minutes they became fo hard that when they were pierced with a pin they cracked like the fhell of a pullet's egg. The liquor that iffued from them was whitifh like water. When' put into the microfcope, they appeared femi-transparent like a hog's bladder. The next day the fame butterfly had laid 170 eggs making in all fix hundred and one.

The obfervation I have just made to fhew the fertility of infects will likewife prove that eggs are foft when difcharged by the female; this I was convinced of likewife by another experiment. I took a butterfly of another fpecies which I fixed to a board like the other. As foon as it had laid an egg I touched it with the point of a pin, and found that I could make little pits in it, nearly as in a bladder which is not quite blown. Some minutes afterwards thefe eggs became hard, and when I preffed them ftrongly, they broke in feveral places like the eggs of a pullet.

At first nothing is feen but an aqueous matter, a little time however difcovers in the middle, a dark point which afterwards becomes the infect. In this it is entirely enclosed, but it cannot be perceived without the aid of a good microfcope. Under the hard fhell of the egg is found a pellicle, fine and delicate, in which the infect is wrapt up as in a matrix. It is there rolled up with fo much art, that notwithftanding the fallness of its apartment it has abundance of room, and is furnifhed with all the members it ought to have. When we view the furprifing compactnefs and difpofition of the whole, we cannot fufficiently admire the wifdom of him who has confined fo much matter in fo little space. The infect as I have already faid remains in this ftate till having become larger it acquires ftrength fufficient to burft its prifon walls and to come forth.

The little care which infects take of their eggs deferves the reader's attention. After having depofited them, they leave them, and go away without any further concern; they refign the labour of hatching them to the nature of the place where they are laid, and to the heat of the fun. In due time the caterpillars iffue from the eggs without any defence against the injuries of the air. By this they are diftinguished from the reft of all other animals. A woman nourishes and protects the child in her womb for nine months; the females of quadrupeds do the fame with their young; birds lay their eggs in nefts, and hatch them with the most diligent and painful incubation. Fishes alone in this refpect refemble infects; they lay their spawn upon the hore without any other precaution than that of chufing a place they think the inoft proper for depofiting it in; they then abandon it, and the young are brought forth without the affiftance of their parents.

As