HISTORY OF INSECTS. 45 



139. The egg of the fly, which is placed on 

 the neck of the caterpillar, the only part from 

 ■which the caterpillar could not remove it, is very 

 conspicuous to an observer ; in this situation, we 

 cannot vifonder, then, the little ichneumon should 

 discover it ; nor does it appear an improbable 

 supposition, that the little creature seizes this 

 opportunity of piercing its shell with her oviduct, 

 and depositing her egg amidst its contents. 



140. The maggot of the fly, as soon as 

 hatched, pierces the skin of the caterpillar, and 

 commences devouring, carrying within it a horde 

 of insidious parasites, which, though they inter- 

 fere not with the due performance of its appointed 

 work of destruction, yet, in the end, so weaken 

 it, that it never arrives at perfection. 



141. Ichneumons of different kinds attack the 

 eggs, larvas, chrysalides, or imagines, of nearly all 

 insects; and very ingenious experiments and cal- 

 culations have proved, that four out of every five 

 eggs that are laid, are prevented from arriving at 

 maturity by parasites attacking them in one or 

 other of these stages. 



