HYMENOPTERA. 



627 



that the abdomen is attached to the top of the metathorax, 

 and not at the hind end of it, as with other insects. The 

 abdomen is compressed, and has a very slender base. 



The venation of the wings also presents a striking pe- 

 culiarity. In other Hymenoptera vein V of the fore wings 



FIG. 755. Wings of A 



arises from some point on the cross-vein III-VII that is 

 nearer to vein III than to vein VII, while in the Evaniidae 

 the origin of vein V is nearer to vein VII than to vein III. 



F:c. 756. Wings of Fcenus. 



In the more generalized members of the family, as Aulacus 

 (Au'la-cus), the origin of vein V is but a little way from the 



