1 26 JCHNEUlsrONS. 



applied to them, because they are as valuable 

 in their operations for the destruction of insect 

 pests, as the animals so designated are in de- 

 vouring the eggs of crocodiles and serpents, in 

 the regions where they are the terror of the 

 inhabitants. The little ichneumons of the 

 insect world do as great service as the ichneu- 

 mons of Africa, which prevent the dangerous 

 creatures just mentioned from becoming so 

 numerous as to occupy the countries where they 

 abound to the exclusion of other animals, and 

 their own misery from want of food. 



In order to understand how the curious in- 

 sects about to be noticed stay the encroach- 

 ment of our little midges, a few observations 

 are necessary on their general habits. Their 

 peculiar instinct is to lay their eggs in other 

 living insects, mostly when they are in the 

 larva state. Sometimes they oviposit in chry- 

 salides, and occasionally in eggs ; but never, it 

 is believed, in any insect while in a perfect 

 condition. The object of their eggs being thus 

 laid is, that they may under these circumstances, 

 which are favourable to their nature, hatch into 

 gnibs. These grubs or maggots soon com- 

 mence attacking the living substances in which 

 thev were placed, and ultimately destroy them. 



