248 



ELEMENTARY ENTOMOLOGY 



hind legs, are parasitic upon the eggs or larvae of other insects, 

 and belong to a group of families which are the most important 



of parasitic insects. The technical differences 

 between the more common families are based 



FIG. 391. A gall-fly (Cy- 

 iiips quercnssaltratix}, 

 which produces the 

 jumping galls formed 

 on oak leaves. (Much 

 enlarged) 



(After Kellogg) 



FIG. 392. Long-tailed ophion (Ophion 

 macrurum}. (Much enlarged) 



(After Riley) 



upon the wing-venation, and need not be discussed, but the gen- 

 eral habits are somewhat similar. The female lays her eggs either 



FIG. 393. 'Pimpla conquisitor. (Twice natural size) 

 a, female ; , female in act of ovipositing in cocoon of tent caterpillar. (After Fiske) 



