PLECOPTERA OF NORTH AMERICA 



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Genus CAPNIA Pictet. 



1841. Cap nia Pictet, Insectes Neurop., Perlides, 320. 

 1897. Arsapnia Banks, Trans. Amer. Ent. Soc, 24:22. 

 1907. Arsapnia Banks, Cat. Neur. Ins., p. 15. 



Small blackish species, mostly- 

 less than 10 mm. in length. 



Head blackish, wider than pro- 

 thorax; three small ocelli, the 

 hind ocelli closer to the eyes than 

 to each other; a depressed area 

 just back of the hind ocelli; sur- 

 face covered with fine pile. Anten- 

 nae long, dark brown and com- 

 posed of more than twenty-five 

 segments. 



Prothorax as wide or wider 

 than long; surface at most mod- 

 erately rugose ; front angles 

 broadly rounded; sides usually 

 somewhat convex. Legs brown ; 

 middle tarsal segment very short ; 

 first and third tarsal segments 

 subequal. Wings subhyaline to 

 lightly inf uscated ; venation not 

 very heavy and quite regular; 

 subcosta reaches at least three- 

 fourth the distance to the cord; 

 an oblique crossvein beyond the 

 end of subcosta ; one median and 

 one cubital crossvein (not count- 

 ing the end ones) and these op- 

 posite each other; anal field of 

 hind wing only about half as long 

 as wing and not extending back of the cord. 



Abdomen brown. Cerci or tails long (except A. brevi- 

 cauda, in which the cerci are composed of five or six seg- 

 ments) usually as long or longer than the entire body and 

 composed of somewhere near twenty segments. 



Male. Supra-anal process recurved over the abdomen in 

 the form of a probe; subanal lobes small, triangular, up- 

 curved, ninth abdominal sternite slightly produced and 

 evenly rounded behind, without a ventral appendage. 



Female. Eighth abdominal sternite not produced into 

 a distinct subgenital plate. 



Fig. 28. 



Capnia vernalis 

 Newp. 



