84 University of California Publications. [Entomology 



Resume. — Among the methods of modification of the simple 

 type of venation, those dependent upon the coordination of the 

 two pairs, as we have seen, involve various special modifications 

 of the immediately adjacent parts, as well as a general adjust- 

 ment of the whole wing areas. The coordination to parts of the 

 body is of another kind, appertaining to the wing at rest rather 

 than in flight, and so is best seen in wings modified as elytra. 

 In the hind wing the arrangements for folding are dependent 

 upon this elytral modification of the front wing. There is a 

 normal method of increase or decrease of veins, which does not 

 result in any particular specialization. The reduction in the 

 number of the cross veins is usually true specialization, because 

 it is not usually a process involving the whole wing, unless it be 

 associated with decrease in size. The surviving cross veins may 

 owe their preservation to their becoming continuous with longi- 

 tudinal veins, or with each other. 



