254 THOMAS SAY FOUNDATION 



Genotype, Capnia nigra Pict. (European). 



Capnia rental is Newpt. is the only species of this genus 

 from east of the Rocky Mountains. This genus replaces 

 Capnella west of the Rocky Mountains. It differs from 

 Capnella in the more regular venation, a longer subcosta, 

 and a shorter anal field in the hind wings. 



The males show very distinct specific differences in the 

 structure of the genitalia, but the females can at present 

 not be definitely separated and no attempt has been made 

 to include an analytic key to the females in the species 

 which are known. 



Key to the Species of Capnia. 



Males. 



1. Supra-anal process divided into two or three parts 2 

 Supra-anal process composed of a single recurved 



probe 4 



2. Supra-anal process composed of two parts, sub- 



equal in length 3 



Supra-anal process composed of three parts, a 

 lower excavated sheath, reaching to the sev- 

 enth abdominal tergite and two upper processes 

 extending about two-thirds the length of the 

 lower sheath ; seventh abdominal tergite with 

 a small median raised process barberi 



3. Seventh abdominal tergite with a median, raised, 



granulate knob ; supra-anal processes slender, 



gradually tapering to blunt points manitoba 



Seventh abdominal tergite without a definite me- 

 dian raised knob (although the tergite is 

 humped) ; supra-anal processes each enlarged 

 toward the tip and bifid columbiana 



4. Supra-anal process slender, gradually tapering to 



a point 5 



Supra-anal process enlarged beyond the base 11 



5. Seventh abdominal tergite with a distinct raised 



knob or button 6 



Seventh abdominal segment smooth, without a 

 raised knob or button 7 



6. Knob on seventh abdominal tergite circular, 



coarsely granulate, extending considerably over 

 the hind margin of the seventh tergite; supra- 



