THE GENUS PISSODES. 31 



d2. Posterior Ijrown spots small. 



el. Elytral interspaces 3 and 5 clevalcd and broad. 



Posterior spots iused, the yellow one larger. Mani- 

 toba - 9. canadensis. 



Posterior spots usually separated, yellow one small. 

 Elytra noticeably narrowed posteriorly from base. 



10. nemorensis. 

 Elytra not noticeably narrowed posteriorly from 



base. South Atlantic States 11. deodarse. 



Elytra noticeably narrowed posteriorly; white and 

 brov/n spots separated, the latter very small. 



12. californicun. 

 e2. Elytral interspaces 3 and 5 narrow, strongly elevated. 

 Pronotal punctures coarse but not dense. . 13. yosemite. 



Pronotal punctures coarse and dense 14. webbi. 



a2. Elytra with transverse band of white and yellow scales near vertex. 



hS. Pronotum with posterior angles acute 15. radiatae. 



b4. Pronotum with posterior angles subrectangular 16. fasciatus. 



B. Elytra usually without distinct anterior spots, and with posterior spot anterior 

 to vertex of declivity. 



aS. Pronotum with basal angles subrectangular 17. costatus. 



a4. Pronotum with basal angles rounded. 



b5. Pronotal punctures distinctly separated. 



c5. Pronotum not distinctly narrower than elytra. 



dS. Pronotum stout, deeply constricted anteriorly.. 18. fiskei. 

 d4. Pronotum subehmgate, not deeply constricted anteriorly. 

 Pronotum moderately stout; elytral interspaces 3 and 5 



scarcely elevated; with anterior spot 19. nigrae. 



Pronotum elongate. 



Elytral interspaces 3 and 5 slightly elevated, flattened; 



with anterior spot 20. puncticollis. 



Elytral interspaces 3 broader and more elevated; with- 

 out anterior spot 21. murrayanae. 



c6. Pronotum distinctly narrower than elytra. 



Pronotal punctures irregular, not dense; punctures of striae 



irreo-ular 22. coloradensis. 



Pronotal punctures regular, moderately dense; punctures of 



striae coarse, irregular 23. alascensis. 



Pronotal punctures dense, regular; punctures of striae irregular. 



24. rotundatus. 

 be. Pronotal punctures irregular, not distinctly separated. 

 ('7. Elytral striaj with punctures very irregular. 



Gray, densely clothed with scales; spots prominent. 25. burkei. 

 Black, not densely clothed with scales; spots obscure. 26. piperi. 

 cS. Elytral striae with punctures moderately irregular; spots obscure. 

 Pronotum convex, without dorsal impressions and elevations. 



27. dubius. 

 Pronotum moderately convex and usually with dorsal impres- 

 sions and elevations 28. fraseri. 



II. Elytral interspaces 3 and 5 not broader or more elevated than 2 and 4. 



Elytra with distinct posterior spots 29. affinu. 



Elytra with small posterior spots 30. curriei. 



