WASP GElSrUS CERCERIS — SCULLEN 343 



6. Entire medial lobe of the clypeus elevated into a cone flanked by single but 



less prominent pointed processes on each lateral lobe .... Group IV 



Clypeal elevation or process not flanked by smaller processes on the lateral 



lobes Group V 



7. Lateral apices of the clypeal process considerably prolonged, giving the 



appearance of horns or the points of a new moon 8 



Lateral apices of the clypeal process, if any, not greatly prolonged ... 12 



8. Secondary lateral apices on the sides of the clypeal process . alceste Mickel 

 No secondary lateral apices on the sides of the clypeal process 9 



9. Small species, approximately 10 mm. in length .... dentifrons Cresson 

 Species of medium to large size, 15 mm. or more in length 10 



10. Distinctly black with creamy white markings .... stigmosalis Banks 

 Black with yellow markings 11 



11. Apical mandibular denticle subequal to or smaller than the other denticles; 



distance between apical and medial denticles about one-half mm., medial 

 and basal denticles confluent; clypeal process horns very long, curved, 

 and acute; no yellow on the 6th tergum (Central States) . . . sexta Say 

 Apical mandibular denticle noticeably larger than the other denticles; 

 distance between all denticles subequal; 6th tergum yellow to the sides 

 of the pygidium (west of the Rocky Mountains and into Mexico) . 



tepaneca Saussure 



12. Clypeal process width subequal to or greater than the length 13 



Clypeal process noticeably longer than the width 27 



13. Clypeal process very short, little more than a curved carina 14 



Clypeal process length subequal to its width 15 



14. Length 13 to 15 mm.; band on tergum 2 much broader than other abdominal 



bands but deeply emarginate halone Banks 



Length 10 to 11 mm.; bands on terga 2 to 5 subequal deserta Say 



15. Clypeal process relatively flat above 16 



Clypeal process convex above 18 



16. Free margin of the clypeal process showing very little emargination, lateral 



apices not acute, minute medial denticle on the margin (Eastern States 



from Kansas to the New England States) banks! ScuUen 



Free margin of the clypeal process with considerable emargination, lateral 

 apices acute, margin without a medial denticle 17 



17. Legs amber with no yellow markings (Texas) texana ScuUen 



Hindfemora largely yellow with amber at the apical end only (Central Plains 



States from North Dakota to Texas) . . . occipitomaculata Packard 



18. Sides of clypeal process subparallel 19 



Sides of clypeal process converging 21 



19. Creamy yellow markings (Northern States from coast to coast) . 



nigrescens nigrescens F. Smith 

 Yellow markings 20 



20. Somewhat more robust; lateral apices of clypeal process less acute (California 



and bordering states) nigrescens munda Mickel 



Lateral apices of the clypeal process very acute (Northeastern States) . 



nigrescens arelate Banks 



21. Tergum 1 and anterior part of tergum 2 largely ferruginous; free margin of the 



clypeal process rounded ^vyomingensis Scullen 



Black with creamy white or yellow markings only 22 



22. Markings yellow 23 



Markings creamy white 25 



