344 PROCEEDINGS OF THE NATIONAL MUSEUM vol. ii6 



23. Band on tergum 2 broader than on other terga; clypeal process emarginate 



(Eastern States, rarely west to North and South Dakota, Nebraska, and 



Kansas) atramontensis Banks 



Bands on terga 2 to 5 subequal in width 24 



24. Apex of clypeal process rounded (California and bordering states) . 



aequalis aeqiialis Provancher 



Apex of clypeal process somewhat truncate and emarginate (California and 



bordering areas) varians Mickel 



25. Apical end of the clypeal process acute or rounded, not emarginate (Idaho, 



adjoining areas, and mountains of central New Mexico). 



aequalis idahoensis Scullen 

 Apical end of the clypeal process slightly emarginate 261 



26. Apical denticle on the mandible the larger; lateral apices of the clypea 



process not extended (Rocky Mountains, west to eastern Washington' 

 east to North Dakota, north to Alberta, and south to northern Texas). 



calochorti Rohwer 

 Medial denticle on the mandible the larger; lateral apices of the clypeal 

 process extended to form a distinct denticle (southern California). 



macswaini Scullen 



27. Clypeal process sides distinctly converging to a smaller apex 28 



Clypeal process sides subparallel 31 



28. Markings showing considerable ferruginous or amber (eastern slope of the 



Rocky Mountains and adjoining areas) vicina Cresson 



Markings black and yellow or cream, no ferruginous or amber 29 



29. Markings black and white; apex of clypeal process rounded. 



aequalis bolingeri Scullen 

 Markings black and creamy yellow; apex of clypeal process truncate . . 30 



30. Pygidium sides subparallel (Central and Northeastern States). 



astarte Banks 

 Pygidium sides converging to a narrow apex . . clyjKjata dakotensis Banks 



31. Bands on terga 2 to 5 broad and not emarginate. morata Cresson (in part) 

 Bands on terga 2 to 5 not all broad, some narrow or emarginate .... 32 



32. Bands on terga 2 to 5 subequal in width; tergum 1 with considerable fulvous. 



nebrascensis H. S. Smith 

 Band on tergum 2 broader than those on terga 3 to 5 33 



33. Markings with considerable amber or shades of brown. 



morata Cresson (in part) 

 Markings black and yellow, no amber or brown 34 



34. Band on tergum 2 deeply emarginate (Eastern States, rarely in the Central 



States) clypeata prominens Banks 



Band on tergum 2 with little or no emargination 35 



35. Bands on terga 3 to 5 narrow but unbroken and broad laterally; band on 



tergum 2 sometimes slightly emarginate (Eastern States, rarely west to 



the Great Plains) clypeata clypeata Dahlbom 



Bands on terga 3 to 5 absent or reduced to lateral spots; band on tergum 2 

 not emarginate (Great Plains, rare in the East) . clypeata gnarina Banks 



36. Large species, 16 mm. or longer 37 



Small species, 12 mm. or less in length 42 



37. Clypeal process with a single acute apex verticalis F. Smith 



Clypeal process bicuspidate 38 



