Vol. 1.] 



Woodivortli. — Wing Vei)is of Insects. 



15 



from the beginning project dorsally, and thus appear to be 

 outgrowths of the pleurae. Comstock and Needham ('98-99) 

 remark that "they appear at a time when the tergum and 

 pleura are very little chitinized and are hardly more identified 

 with one than with the other." The wingpads in Odonata also 

 differ from those of most of the lower insects in that they 

 arise from the middle of the segments and only later extend 

 forward and backward across their whole width. 



Among the higher insects the wings seem uniformly to 

 arise from the middle of their respective segments somewhat 

 dorsal of the legs, but at a time when there is no evident dif- 

 ferentiation of dorsum and pleura. They usually appear well 



FIG. 2. Dia^rani illustrating the relation of the wint; to the 

 dorso-pleural suture. 



1. The commonly received view. 



2. Comstoclc and Needham's view. 



3. Calvert's view. 



u, notum; p, pleura; w, wing; .s, suture. 



up toward the back and lie in such a position that the tip is 

 directed downward and posteriorly, giving one quite the same^ 

 impression as do most of the wingpads in the lower insects, 

 viz., that they are processes of the dorsum. Packard ('98) 

 goes still further in the case of the Hymenoptera by regarding 

 the wing fundaments as scutal structures. No one else has 

 attempted to locate them so closely, but their derivation from 

 the notum has been the conception of nearly all those who 

 have expressed any opinion in the matter. Two very recent 

 authors, however, have given expression to other and entirely 

 distinct views. 



Calvert ('93) says, while discussing the Odonata, that the 

 upper lamina is " tergal and the lower pleural," and presum- 

 ably maintains the same for other insects. No evidence is 

 cited in favor of this view. Comstock and Needham ('98-99) 

 incidentally give expression to another idea by describing the 



