200 THOMAS SAY FOUNDATION 



pointed process; supra-anal process very com- 

 plicated prolongata 



12. Supra-anal process greatly enlarged beyond the 



base (side view) and largely membranous 13 



Supra-anal process not enlarged beyond the 

 base (side view) and largely chitinized 16 



13. Wings and legs not banded with darker and 



lighter colors; subanal lobes entire, somewhat 



prolonged frigida 



Wings and legs more or less distinctly banded ; 

 subanal lobes broad and (ventral view) bearing 

 on the inside a small spine-like appendage 14 



14. Supra-anal process armed below with two rows 



of spines, also with a few spines above 



oregoncnsis 



Supra-anal process unarmed 15 



15. Cerci very small; ventral lobe truncate; subanal 



lobes (side view) with a pointed projection be- 

 low; small species, 6.5 mm. long columbiana 



Cerci quite large, ventral lobe rounded; subanal 

 lobes (side view) smooth below ; larger species 

 9-10 mm. long cinctipes 



16. Each side of the tenth tergite greatly prolonged 



backward and armed with spines; ventral lobe 



as wide as long rotund./ 



Sides of tenth tergite not prolonged backward, or 

 if apparently so there are no spines present; 

 ventral lobe at least twice as long as wide 17 



17. Subanal lobes (ventral view) unmodified, i. e. 



evenly rounded 18 



Subanal lobes modified (prolonged, bifurcate, 

 divided, etc.) 20 



18. Supra-anal process short, broad, truncate at tip, 



partly membranous, bearing above two chiti- 



nous projections delicatula 



Supra-anal process long, slender, pointed and en- 

 tirely chitinized 19 



19. From the base of the supra-anal process, on each 



side originates a long, slender diverging chiti- 



nous process divergens 



No diverging slender chitinous process originat- 

 ing from the base of the supra-anal process 



glab ";/ 



20. Wings with many (about 30) clear rounded spots 



disposed over the entire surface, supra-anal 



