164 PROC. ENT. SOC. WASH., VOL. 22, NO. 7, OCT., IQ2O 



Interaler band present, more or less distinct 6 



2. Pleura with lower half covered with dark pile perplexus 



Pleura covered with yellow pile to bases of legs 3 



3. Ocelli large, placed well below the supraorbital line, lateral ocelli nearer 



the margins of the eyes than to each other separatus 



Ocelli small, near supraorbital line, lateral ocelli not nearer margins of 

 eyes than to each other 4 



4. Malar space wider at apex than long impatiens 



Malar space as long or longer than width at apex 5 



5. Hypopygium with median carina on apical portion, second segment yel- 



low vagans 



Hypopygium with no median carina, usually some black on second seg- 

 ment bimaculatus 



6. Ocelli large, placed well below supraorbital line, lateral ocelli nearer the 



margins of the eyes than to each other 7 



Ocelli small, near supraorbital line, lateral ocelli not nearer eye margins 

 than to each other 8 



7. Not more than first two dorsal abdominal segments with yellow pile 



fraternus 



Usually with yellow pile on first three segments, first segment sometimes 

 entirely dark auricomus 



8. Second segment with brownish red pile affinis 



Second segment yellow 9 



9. Only first three segments with yellow pile pennsylvanicus 



First four segments with yellow pile fervidus 



Males. 



1. Eyes swollen, ocelli well below supraorbital line 2 



Eyes not swollen, ocelli on or near supraorbital line 4 



2. Malar space a mere line fraternus 



Malar space one-third as long as wide 3 



3. More than first two dorsal abdominal segments covered with yellow 



pile auricomus 



Not more than first two segments with yellow pile separatus 



4. Interaler band present 1 5 



No interaler band, at most a few black hairs on disk 7 



5. Third dorsal abdominal segment black affinis 



Third dorsal adbominal segment yellow 6 



1 Mr. J. C. Crawford tells me that some western specimens of pennsyl- 

 vanicus have the interaler band almost totally lacking. Should such spec- 

 imens be found here they may be readily distinguished from perplexus, where 

 they would run in this key, by having yellow pile on first four segments of 

 abdomen. 



