REVISION OF GENUS EUCERCERIS CRESSON 7 



9. A distinct truncate cone-shaped elevation on the frons just above the 



epistomal suture sonorae, new species 



No elevation on the frons above the epistomal suture 10 



10. Ferruginous with yellow markings (mostly in the Southwest but recorded 



from central California to the Missouri River and from Montana to central 



Mexico) canaliculata canaliculata (Say) 



Fuscous to black with yellow markings (scattered records in Utah, southern 

 Arizona, western Texas, and central Mexico) 



canaliculata atronitida ScuUen 



11. Enclosure densely and completely punctate, not ridged 12 



Enclosure smooth or ridged; if punctures are present, they do not cover 



entire enclosure 14 



12. With a pan- of blunt denticles on the margin of the medial lobe of the clypeus; 



1st and 2nd terga immaculate (known only from the states of Puebla and 



Oaxaca in Mexico) stangei, new species 



With a single broad rounded process on the medial clypeal lobe; 1st and 2nd 

 terga with light markings 13 



13. Narrow creamy white bands on the terga (southern Arizona, southern New 



Mexico, Baja California, and Sonora, Mexico) .... angulata Rohwer 

 Broad yellow bands on terga (Rocky Mountains, Mont. S. to central Mexico) 



montana Cresson 



14. Distinct but often small elevations on the surface of the medial clypeal 



lobe (not just a convex surface) 15 



No distinct elevation or denticle on the surface of the medial clypeal 

 lobe 22 



15. Mandibles with a single subbasal or medial tooth on inner margin ... 16 

 Mandibles with two subbasal or median teeth on inner m.argin .... 19 



16. Five denticles on the medial clypeal border, the mesal one smaller than 



the others; considerable amber on most of the dorsal parts (Chisos Moun- 

 tains, Tex., limited records from New Mexico and Chihuahua, Mexico) 



mellea ScuUen 

 Less than five denticles on the medial clypeal border 17 



17. Four distinct subequal denticles on the medial clypeal margin and these 



subequally spaced (Rocky Mountain states from Montana to the Mexican 



border) fulvipes Cresson 



Two widely separated denticles on the clypeal border between which there 

 is usually a bicuspid medial extension 18 



18. Considerable amber on dorsal parts rubripes Cresson 



Amber markings, if any, largely on ventral parts; medial extension not always 



bicuspid melanovittata Scullen 



19. The more basal denticle of the mandible much the larger of the two; largely 



amber and yellow (widely scattered over the Southwest and into northern 



Chihuahua, Mexico) apicata Banks 



The more basal denticle of the mandible much the smaller; two widely sepa- 

 rated denticles on the clypeal margin; body black and creamy white . . 20 



20. Pygidium noticeably narrowing basally (arid sections west of the Rocky 



Mountains) vittatifrons Cresson 



Pygidium not noticeably narrowing basally 21 



21. A small blunt single elevation on the surface of the medial lobe of the clypeus 



(Southwestern states, California to New Mexico) . . . arenaria Scullen 



