PAEASITKS. 



269 



nourishment of their youno:, and the predators in gfcneral feed themselves 

 iTpon living' insects. 



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

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

 not unlike wasps in appearance, which lay their egg's on or in the bodies of 

 caterpillars, the larva which hatches 

 nourishing" itself at the expense of 

 its host (%. 321). The caterpillar 

 continues to live and feed, moulting" 

 as usual; the parasite meanwhile 

 g-rows 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 jive 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. 



I^ead Caterpillar showing hole of etnergence 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 



