210 



SUBKINGDOH ARTICULATA. 



Cynipidae. The Gall-fly 

 produces the gall-nuts used in 

 making ink. It punctures the 

 leaves and other parts of certain 

 plants, especially the oak, and 

 deposits an egg in the wound, 

 with some irritating fluid that 

 causes the excrescence. 



Ichneumonidae (hunter 

 family). The Ichneumons 

 number more than six thousand 

 species. Their mission is to 

 prevent the increase of other 

 insects. They are furnished 

 with an auger by which they 

 introduce their eggs underneath 

 the skin of caterpillars. The 

 maggots feed upon the body of 

 their victims. With wonderful 

 discrimination, however, they 

 consume only the adipose part, 



and spare its vitals until they are themselves ready to enter 



the pupa state. 



Fig. 360. 



Cynips quercus-folii, Gall-fly. 



Ichneumon manifettator, 

 Ichneumon Fly depositing its eggs in the larvae at the bottom of the holes. 



