THE TENT CATERPILLAR PARASITE. 



Pig. 8. — Tent Caterpillar 

 killed by a Parasite. 



In many of the nests of the tent caterpillars you can find 

 peculiarly shrunken caterpillar skins, looking like Fig. 8. The 

 under side is generally split open and 

 shows part of a silken cocoon. 



These are the remains of caterpillars 

 which have been killed by parasites. 

 Weeks before, when the caterpillars were 

 rather small, an egg was deposited in each 

 by a four- winged fly, resembling in general 

 appearance Fig. 11. The egg hatched into 

 a tiny maggot, which grew by absorbing 

 the juices of the caterpillar's body. fig. 9. - Parasitic Maggot. 



In two or three weeks the maggot became 

 so large that the caterpillar was killed and 

 nothing was left of it but the skin with the 

 parasite on the inside. The latter then 



Fig. 10. — Pupa of 

 Parasite. 



spun a silken cocoon, within 

 which it changed to a pupa 

 (Fig. 10). 



A short time afterwards an- 

 other change takes place and 

 from the pupa there emerges 

 a fly similar to the one which 

 laid the egg in the young 

 caterpillar (Fig. 11). This fly 

 is called an ichneumon fly. 



The tent caterpillars have 

 many enemies besides these ichneumon flies. While their 

 hairy skins protect them from the attacks of many birds, there 



10 



Fig. 11. — Ichneumon Fly. 



