HYMENOPTERA. 



235 



CHALCIDID^. 



The Chalcididse are mostly small in size, and are par- 

 asitic upon the eggs or larvae of other insects. Accord- 

 ing to Westwood, the males of the genus Blastophaga 

 are wingless, while the females are winged, which is 

 exceptional among insects. 



ICHNEUMONID.^. 



Fig. 185, natural size, represents an ichneumon-fly, 

 Thalessa atrata, Fabr., which was collected by a boy 



Fig. 185. 



of thirteen from one of our common shade trees. 

 The power possessed by the insects of raising and 

 lowering the abdomen, and the efficient aid given, in 



