THE WINGS OF PLECOPTERA 



251 



In certain closely allied forms, the coalescence is complete with the result 

 that the radial sector is not branched. In the hind wing of this species the 

 homology of the veins is somewhat obscured by an anastomosis of veins 

 Ms +4 and Cui. 



In Eusihenia speciahilis (Fig. 246), the most "richly veined" member of 

 the family that I have seen, the two-branched condition of both the radial 

 sector and of media of both fore and hind wings is perfectly preser\^ed. 



The Nemouridae. — In Nemoiira (Fig. 248) the plecopterous type is per- 

 fectly prescr^•cd in both fore and hind wings. A detailed discussion of the 

 wings of Nemotira follows on a later page. 



The Perlidae. — In the fore wing of Chlorcperla sp. (Fig. 249), the radial 

 sector and the media are clearly only two-branched; the same is true of 

 the hind wing except that the homology of the veins is somewhat obscured, 

 as in Gripopteryx, by an anastomosis of veins M3+4 and Cui. 



/?4+5 



2d A 



Fig. 249. — -Wings of Chloroperla sp. 



The Capniidae. — In the Capniidae there appears to be a degeneration of 

 the wing-venation, which has resulted in a remarkable lack of constancy in 

 the courses of the veins, even within the limits of a single species. But it 

 is easy to find examples, at least of fore wings, in which the plecopterous 

 type of venation is fairly well preserved (Fig. 250). 



