« 上一頁繼續 »
bars of them should be destroyed, that lojs would be easily repaired by the fertility of the females. One insect generally lays a great number of eggs; from thirty to sixty and even some hundreds. This I learnt by the following circumstance. On the 6th of June 1736, a forester brought me a butterfly, the upper wings of which were dark, spotted 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 dav, found that it had laid four hundred and thirty one eggs of the size of a grain of millet, which resembled small pearls. At first they were soft, as I easily perceived because they were flat on that side which rested on the board, and resembled the top of a loaf. Their figure cannot be observed while they lie one upon another; they must be detached to have a distinct view of them. In ten minutes they became so hard that when they were pierced with a pin they cracked like the shell of a pullet's egg. The liquor that issued from them was whitish like water. When put into the microscope, they appeared semi-transparent like a hog's bladder. The next day the fame butterfly had laid 170 eggs making in all six hundred and one.
The observation I have just made to shew the fer* tility of insects will likewise prove that eggs are soft when discharged by the female; this I was convinced of likewise by another experiment. I took a butterfly of another species which I fixed to a board like the other. As soon 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. Soir.e minutes afterwards these eggs became hard, and when 1 pressed them strongly, they broke in several places lik.c the eggs of a pullet. . .
H 2 , At
At first aothing is seen but an aqueous matter, ai little time however discovers 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 microscope. Under the hard shell of the egg is found a pellicle, fine and delicate, jn which the insect is wrapt up as in a matrix. It is there rolled up with so 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 surpriGng compactness and disposition of the whole, we cannot sufficiently admire the wisdom of him who has confined so much matter in so little space. The insect as I have already said remains in this state till having become larger it acquires strength sufficient to burst itsprison walls and to come forth.
The little care which insects cake of their eggs deserves the reader's attention. After having deposited them, they leave them, and go away without any further concern; they resign 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 issue from the eggs without any defence against the injuries of the air. By this they are distinguished from the rest 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 nests, and hatch them with the most diligent and painful incubation. Fishes alone in this respect resemble insects; they lay their spawn upon the shor,e without any other precaution than that of chusing a place they think the most proper for depositing it in; they then abandon it, and the young are brought forth without the assistance of their parents.
As Infects produce such a number of eggs' it is easy 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 insects. The author of the Book of Judges ia order to give an idea of the multitude of Midianites, and Amalekites, fays, that " they came with their "cattle as grasshoppers for multitude, and they en
"tered into the land to destroy it." Judges vi. 5.
The Prophet Jeremiah makes the fame comparison in speaking of the troops which Nebuchadnezar was to bring into Egypt. "They shall come against her "with axes, as hewers of wood. They ihall cut "down her forest, faith the Lord, though it cannot "be searched, because they are more than the grasshop** pers, and are innumerable." Cap. Xlvi. 22,23. The miseries that were to afflict Nineveh the great, are represented by Nahum under emblems drawn from insects. 'Make thyself many, says that Pro'phet, as the canker-worm, make thyself many as
* the locusts. Thou hast multiplied thy merchants,
* above the stars of Heaven; the canker-worm spoi
* leth and flieth away. Thy crowned are as the lo'cuds, and thy captains as the great grasshoppers, 4 which camp in the hedges in the cold day, but 'when the fun ariseth they flee away, and theii place
* is not known.' Chap. Hi. 15,16,17.
One thing which contributes greatly to the prodigious multiplication of insects is the little time they require from their exclusion by the parent female to their being capable of laying eggs themselves. This is so rapid as to have given occasion to a vulgar saying that the louse may be in four and twenty hours a mother, .a grand-mother and a great grand mother. We must not therefore be surprised that insects multiply so remarkably, and that such pains are requisite to destroy them.
What I have said in this Chapter might furnish abundant matter for reflection. It is allowed that insects are destitute of reason; the wisdom therefore of their conduct, the justness of their precautions, and in a word every thin.-- they do which is agreeable to reason, does not proceed froni themselves From whom then do they derive if? \Vho hath taught them the ser.fon and the manae- of propagating their species? Who hath directed diem to lye with such compactness in their eggs withour being in the least uneasy ? How do they knt <jv the precise moment when it is proper to issue from their eggs? Who harh prescribed to each species the number of ejrgs it is to' lay? Who hath endowed them wish the power of resisting the inclemencies of the weather znd of coming forth without incubation ? (Jrrmust be wilfully blind not to acknowledge in these traces the hand of an all powerful Being whose wisdom is unsearchable. Who but he could have made them capable of so many different functions and have endowed them with instinct to perform them? A grea* number of eggs of insects perish, and animals devour another parr. • Had nor providence supply<;d the loss by the promptitude with which they encrease and their great fertility, the various species vculd have been in danger of perishing, or at L?.st would not have been produced in sufficient quantities to feed the other animals that depend on them.
Of The Transformation Of Insects.
T/he subject I am to treat of in this Chapter is sq singular, that it is peculiar to insects alone ; and as there is nothing resembling it among the other animals, it deserves our particular notice ; and the rather because if we are not attentive to the transfor-r mations of insects, and do not know exactly all the forms which the fame individual successively assumes, we shall be in danger of making two or more infects of one and the fame animal.
It is not the actual substance of the insect which undergoes a transformation; it is merely the external form which is changed. The parts it is composed of, after its metamorphosis, are enveloped and masked as it were under different skins, from which the ar.im'a! disengages itself, successively, as it grows in bulk, and at last appears wiih all the members necessary for it in its last state. When the period of transformation arrives we often fee caterpillars quiring the leaves and plants they have hitherto fed on, and transporting themselves to a more commodious place. Some however do not abandon their first situation, but attach themselves to the stems nr branches of the plant which has formerly afforded them protection and support. '1 hen as if loathing the food jhey had at first greedily devoured, they cease altoge