178 CHARLES ROBERTSON. 



1. Malar space a little shorter than wide ; joints 3 and 4 subequal ; segment 2 at 



most with a little yellow on basal middle virginicus. 



Malar space longer than wide; joint 3 longer than 4; segment 2 largely yel- 

 low 2, 



2. Joint 3 usually as long as 5 ; segment 2 more or less black on the sides and 



apical middle, 4 sometimes a little yellow riding-sii. 



Joint 3 shorter than 5 ; segment 2 yellow consimilis. 



PSITHYRUS Lepeletier. 

 Females. 



Abdomen finely punctured, pubescence short, fine, black, rarely a little yellow 

 on lateral apical margins of segment 4; pleura and space between 

 wings black ; wings darker variabilis. 



Abdomen coarsely punctured, pubescence long, coarse, blunt, segment 3 usually. 

 1, 2 and 4 often, more or less yellow laterally; pleura yellow; meso- 

 notum yellow, with some black hairs on disc; wing paler. 



laboriosus. 



Males. 



Abdomen with lateral apical margins of segments 3-4, basal angles of 5, and 

 sometimes sides of 1 and 2, yellow variabilis. 



Abdomen with segment 1, and 2 except basal angles, yellow ; 3 yellow, or black, 

 with sides yellow laboriosus. 



Carlinville, Illinois. 



