網頁圖片
PDF
ePub 版

bers of them fhould be deftroyed, 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 spots, 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 size of a grain of millet, which refembled fmall pearls. At firft they were foft, as I eafily perceived becaufe they were flat on that fide which refted on the board, and refembled the top of a loaf. Their figure cannot be obferved 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 discharged 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 notwithstanding the smallness of its apartment it has abundance of room, and is furnished with all the members it ought to have. When we view the furprising compactness and difpofition of the whole, we cannot fufficiently admire the wisdom of him who has confined fo much matter in fo little space. The infect as I have already faid remains in this state till having become larger it acquires ftrength fufficient to burst its prifon walls and to come forth.

The little care which infects take of their eggs deferves the reader's attention. After having deposited 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 caterpil lars iffue from the eggs without any defence against the injuries of the air. By this they are distinguished 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 resemble infects; they lay their spawn upon the fhore without any other precaution than that of chufing a place they think the moft proper for depofiting it in; they then abandon it, and the young are brought forth without the af fiftance of their parents.

As

66

As infects produce fuch a number of eggs it is eafy to conceive that there must be a proportionable number of the animals themselves. It is no doubt for this reason that the Scriptures compare numerous armies to infects. The author of the Book of Judges in order to give an idea of the multitude of Midianites, and Amalekites, fays, that "they came with their "cattle as grafshoppers for multitude, and they en"tered into the land to deftroy it.". -JUDGES VI. 5. The Prophet Jeremiah makes the fame comparifon in fpeaking of the troops which Nebuchadnezar was to bring into Egypt. They fhall come against her " with axes, as hewers of wood. They fhall cut "down her foreft, faith the Lord, though it cannot "be fearched, because they are more than the grafshoppers, and are innumerable." CAP. XLVI. 22,23. The miferies that were to afflict Nineveh the great, are reprefented by Nahum under emblems drawn from infects. Make thyfelf many, fays that Prophet, as the canker-worm, make thyfelf many as the locufts. Thou haft multiplied thy merchants, above the stars of Heaven; the canker-worm fpoileth and flieth away. Thy crowned are as the locufts, and thy captains as the great grafshoppers, • which camp in the hedges in the cold day, but when the fun arifeth they flee away, and their place • is not known.' CHAP. III. 15,16,17.

ct

One thing which contributes greatly to the prodigious multiplication of infects is the little time they require from their exclufion by the parent female to their being capable of laying eggs themfelves. This is fo rapid as to have given occafion to a vulgar faying that the loufe may be in four and twenty hours a mother, a grand-mother and a great grand mother. We muft not therefore be furprifed that infects multiply fo remarkably, and that such pains are requifite to deftroy them.

What

[ocr errors]

What I have faid in this Chapter might furnish a bundant matter for reflection. It is allowed that infects are deftitute of reafon; the wifdom therefore of their conduct, the juftness of their precautions, and in a word every thing they do which is agreeable to reafon, does not proceed from themfelves. From whom then do they derive it? Who hath taught them the feafon and the manner of propagating their fpecies? Who hath directed them to lye with fuch compactnefs in their eggs without being in the leaft uneafy? How do they know the precife moment when it is proper to iffue from their eggs? Who hath prefcribed to each ipecies the number of eggs it is to lay? Who hath endowed them with the power of refifting the inclemencies of the weather and of coming forth without incubation? Che muft be wilfully blind not to acknowledge in thefe traces the hand of an all powerful Being whofe wif om is unfearchable. Who but he could have made them capable of fo many different functions. and have endowed them with inftinct to perform them? A great number of eggs of infects perith, and animals devour another part. Had not providence fupplyed the lofs by the promptitude with which they encreafe and their great fertility, the various fpecies would have been in danger of perishing, or at left would not have been produced in fufficient quantities to feed the other animals that depend on them.

[merged small][ocr errors]

CHAP. VII.

OF THE TRANSFORMATION OF INSECTS,

THE fubject I am to treat of in this Chapter is fo fingular, that it is peculiar to infects alone; and as there is nothing refembling it among the other animals, it deferves our particular notice; and the rather because if we are not attentive to the transfor mations of infects, and do not know exactly all the forms which the fame individual fucceffively affumes, we fhall be in danger of making two or more infects of one and the fame animal,

It is not the actual fubftance of the infect which undergoes a transformation; it is merely the external form which is changed. The parts it is compofed of, after its metamorphofis, are enveloped and masked as it were under different fkins, from which the animal difengages itfelf, fucceflively, as it grows in bulk, and at last appears with all the members neceffary for it in its laft ftate. When the period of transformation arrives we often fee caterpillars quiting the leaves and plants they have hitherto fed on, and tranfporting themfelves to a more commodious pláce. Some however do not abandon their first fituation, but attach themselves to the ftems or branches of the plant which has formerly afforded them protection and fupport. Then as if loathing the food they had at firft greedily devoured, they cease altoge

ther

« 上一頁繼續 »