138 



THE WINGS OF ISOPTERA 



and the presence of a network of irregular, slightly chitinized wrinkles, 

 indicated by dotted lines. 



In determining the homologies of the hind wings it is well to begin with 

 the cubitus, which can be easily recognized by the group of prominent 



Kt\-h 



JL. 



^■^T^ 



Fig. 130. 



-The tracheation of a fore wing of a nymph of 

 Termopsis angusHcollis. 



accessory veins near its base; this group of prominent accessory veins 

 borne by cubitus in both fore and hind wings is one of the most characteris- 

 tic features of the wings of termites. Immediately in front of cubitus is the 

 media, which coalesces with vein R4+5 at its base. In front of vein R4+5 

 are two veins; that one of these two which is nearest the costal margin of 

 the wing I believe to be the subcosta and the other, vein R2+3- I am led 

 to this conclusion by the fact that the hind wing of Termopsis angusticollis 

 closely resembles Mastotermes in this region of the wing, and by studies of 

 the tracheation of the wings of Termopsis I have been able to determine the 

 homologies of these veins. 



Back of the cubitus lies the first anal vein. This is simple for the 

 greater part of its length, but is forked near the margin of the wing. The 

 basal part of the first anal vein is very weak, its place having been taken by 

 an anal furrow. The second and third anal veins are much branched, and 

 between them is an axillary furrow. 



The tracheation and the venation of the wings of Termopsis angusti- 

 collis.— An understanding of the tracheation of the fore wings of Masto- 

 termes, illustrated above, renders easy the interpretation of the tracheation 

 of a fore wing of Termopsis angusticollis, which is represented by Figure 130. 



In this wing no costal trachea was found. The subcostal trachea is 

 short, and enters the wing distinct from the radial trachea; only a short 

 vestige of trachea Sci remains. The radial trachea resembles quite closely, 



