14 H. C. FALL. 



Front angles of prothorax distinctly impressed, the hind angles 

 also impressed, but usually less strongly; size large (12— 



14 mm.) 22. brevicollis. 



Front angles of prothorax a little impressed, the hind angles not 

 obviously so; size smaller (9-10 mm.). 



23. semifoveata. 

 Angles of prothorax not impressed; size smaller (8J-10f mm.). 



24. parvicollis. 



12. Mentum without trace of acute transverse ridge; margin of de- 



clivity without erect setae, at least at middle; hind 

 thighs nearly or quite impunctate between the submar- 

 ginal rows of setigerous punctures. 

 Anterior declivity of mentum beginning at apical two-fifths or 

 one- third; tooth of claw nearly median in position. 



Hind coxae nearly or quite impr -tate 25. levicoxa. 



Hind coxae punctate, at least in outer half. 



Prothorax with more or less distinct impressed line along the 

 anterior margin; front angles rather prominent and 



acute; color red brown 26. liaydenii. 



Prothorax without impressed apical marginal line; front 

 angles not prominent. 

 Prothorax less coarsely and densely punctate, elytral 

 punctuation less broadly confused; size smaller, color 

 dark brown or black (Southern Arizona). .27. cleiitella. 

 Prothorax more coarsely and densely punctate, elytral 

 punctuation more broadly confused, size larger, color 

 rufoferruginous in the unique type (Salt Lake Desert). 



28. insigiiis. 

 Anterior declivity of mentum beginning at the middle of its length; 

 tooth of claw slightly, but obviously post-median. 



29. belfragei. 

 Mentum with row of erect setae along the summit of the de- 

 clivity, the transverse arcuate raised line also indicated 

 in sierra; hind thighs irregularly punctate between the 

 submarginal rows of punctures. 

 Form stouter, less than twice as long as wide. 



Ungual tooth subapical in position, punctuation beneath 



sparser and finer (Atlantic region) 30. atlaiitis. 



Ungual tooth only slightly post-median; punctuation beneath 

 much coarser and closer (California and Nevada) . 



31. sierra?. 



Form oblong, parallel, more than twice as long as wide (Rocky 



Mountains of New Mexico and Colorado) .32. parallela. 



13. Thoracic angles not impressed 14. 



Thoracic angles more or less impressed. 



