PARASITES. 



269 



nourishment of their young, and the predators in general feed themselves 

 upon living insects. 



Parasites are found in the majority of species of insects which have 

 been reared in India in captivity. The ' ichneumons ' are Hymenoptera, 

 not unlike wasps in appearance, which lay their eggs on or in the bodies of 

 caterpillars, the larva which hatches 

 nourishing itself at the expense of 

 its host (fig. 321). The caterpillar 

 continues to live and feed, moulting 

 as usual; the parasite meanwhile 

 grows larger and finally causes the 

 death of its host. In many cases 

 the larva comes out of the body, and 

 turns to the pupa outside. In other 

 cases it remains within the dead 

 body until it emerges as a winged 

 insect. Caterpillars containing 

 parasites frequently die before they 

 can become chrysalides ; in some 

 cases they become chrysalides and 



FIG. 323. 



Parasite of the Egyptian Syrphus. 

 (Magnified five times.) 



then die. A caterpillar may contain one or many parasites; as many 

 as seventy small ichneumons have been reared from the body of a Cotton 

 Stem-borer. Ichneumons can be captured in the field or more readily 

 obtained by rearing various caterpillars and grubs, which will yield 

 ichneumons in many cases instead of the perfect insect. Ichneumons 



FIG. 324. 



Dead Caterpillar thowing hole of emergence of parasitic fly grub and the pupa of the 

 grub. (Magnified three times.) 



not only destroy caterpillars but the grubs of beetles, the maggots of 

 flies, and the grubs of bees and wasps. In some cases, one ichneumon 

 lays its eggs within the body of the grub of another ichneumon which is 



