THE WINGS OF HYMEXOPTERA 



379 



(e) AN ILLUSTRATION OF THE REDUCTION OF THE WING-VENATION IN 



HYMENOPTERA 



Having determined the homologies of the wing-veins in the more 

 generahzed members of the Hymenoptera and having attained an under- 

 standing of the various ways in which the typical wing-venation is modified 

 in the more specialized forms, it is now comparatively easy to trace the 



Fig. 400. — Fore wing of Aulacinus Jusiger (.After Bradley). 



Fig. 401. — Fore wing of Evajiia appendigastcr (After Bradley). 



Fig. 402. — Fore wing of Acanthinevania principis. 



homologies of the wing-veins in all of the families of this order in which the 

 venation of the wings is not greatly reduced. 



There are, however, certain families in which the various methods of 

 modifying the primitive type of wing-venation have progressed so far that 

 it is exceedingly difficult to determine the nature of the result and the steps 

 by which it has been reached. It is in this field that lies the greater amount 

 of the work that remains to be done to complete our understanding of the 



