THE ENEMIES OF THE CATERPILLAR. 



each other; and the strongest will devour the 

 weak, in preference to their vegetable food. 

 That which lives upon the oak is found to 

 seize any of its companions, which it con- 

 veniently can, by the first rings, and indict a 

 deadly wound: it then feasts in tranquillity 

 on its prey, and leaves nothing of the animal 

 but the husk. 



But it is not from each other they have the 

 most to fear, as in general they are inoffen- 

 sive j and many of this tribe are found to live 

 in a kind of society. Many kinds of Hies lay 

 their eggs either upon, or within their bodies; 

 and, as these turn into worms, the caterpillar 

 is seen to nourish a set of intestine enemies 

 within its body, that must shortly be its de- 

 struction : nature having taught tlies, as well 

 as all other animals, the surest methods of 

 perpetuating their kind. "Towards the end 

 of August," says Reaumur, "I perceived a 

 little fly, of a beautiful gold colour, busily 

 employed in the body of a large caterpillar, 

 of that kind which feeds upon cabbage. I 

 gently separated that part of the leaf on which 

 these insects were placed, from the rest of 

 the plant, and placed it where I might ob 

 serve them more at my ease. The fly, wholly 

 taken up by the business in which it was em- 

 ployed, walked along the caterpillar's body, 

 now and then remaining fixed to a particular 

 spot. Upon this occasion, I perceived it 

 every now and then dart a sting, which it 

 carried at the end of its tail, into the cater- 

 pillar's body, and then drew it out again, to 

 repeat the same operation in another place. 

 It was not difficult for me to conjecture the 

 business which engaged this animal so ear- 

 nestly ; its whole aim was to deposite its eggs 

 in the caterpillar's body; which was to serve 

 as a proper retreat for bringing them to per- 

 fection. The reptile thus rudely treated, 

 seemed to bear all very patiently, only moving 

 a little when stung too deeply; which, how- 

 ever, the fly seemed entirely to disregard. 

 1 took particular care to feed this caterpillar; 

 which seemed to me to continue as voracious 

 and vigorous as any of the rest of its kind. 

 In about ten or twelve days, it changed into 

 an aurelia, which seemed gradually to de- 

 cline, and died : upon examining its internal 

 parts, the animal was entirely devoured by 

 worms ; whichv however, did not come to per- 



yo. 6~ & 68. 



fection, as it is probable they had not enough 

 to sustain them within." 



What the French philosopher perceived 

 upon this occasion, is every day to be seen 

 in several of the larger kinds of caterpillars, 

 whose bodies serve as a nest to various flies, 

 that very carefully deposite their eggs within 

 them. The large cabbage caterpillar is so 

 subject to ils injuries, that, at certain seasons, 

 it in much easier to find them with than with- 

 out them. The ichneumon lly, as it is called, 

 particularly infests these reptiles,and prevents 

 their fecundity. This fly is of all others the 

 most formidable to insects of various kinds. 

 The spider, that destroys the ant, the moth, 

 and the butterfly, yet often falls a prey to the 

 ichneumon ; who pursues the robber to his 

 retreat, and, despising his nets, tears him in 

 pieces, in the very labyrinth he has made. 

 This insect, as redoubtable as the little quad- 

 ruped that destroys the crocodile, has receiv- 

 ed the same name ; and from its destruction 

 of the caterpillar tribe, is probably more 

 serviceable to mankind. This insect, I say, 

 makes the body of the caterpillar the place 

 for depositing its eggs, to the number of ten, 

 fifteen, or twenty. As they are laid in those 

 parts which are riot mortal, the reptile still 

 continues to live and to feed, showing no signs 

 of being incommoded by its new guests. 

 The caterpillar changes its skin ; and some- 

 times undergoes the great change into an 

 aurelia : but still the fatal intruders work 

 within, and secretly devour its internal sub- 

 stance: soon after they are seen bursting 

 through its skin, and moving away, in order 

 to spin themselves a covering, previous to 

 their own little transformation. It is indeed 

 astonishing sometimes to see the number of 

 Avorrns, and those pretty large, that thus issue 

 from the body of a single caterpillar, and eat 

 their way through its skin : but it is more ex- 

 traordinary still, that they should remain 

 within the body, devouring its entrails, with- 

 out destroying its life. The truth is, they 

 seem instructed by nature not to devour its 

 vital parts; for they are found to feed only 

 upon that fatty substance which composes the 

 largest part of the caterpillar's body. When 

 this surprising appearance was first observed, 

 it was supposed that the animal thus gave 

 birth to a number of flies different from itself; 



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