208 



U. S. NATIONAL MUSEUM BULLETIN 216 



with moderate-sized punctures the interspaces of which are about 1 .3 

 their diameter, the punctures almost lacking on the apical 0.15 ± 

 of the tergite; epipleurum of third tergite truncate posteriorly, the 

 inner margin evenly convex. 



19. Exochus atriceps Walsh 



Figures 188,h; 189,f; 192,j 



Front wing 3.8 to 4.7 mm. long. Structural characters as described 

 under the species group. This is the only Nearctic Exochus with 

 basal half of the lateral longitudinal carina of the propodeum absent. 



There are two subspecies which differ in coloration as described 

 below : 



1. Mesopleurum and abdomen entirely blackish. 



19a. atriceps atricorpus, new subspecies 

 Mesopleurum and abdomen largely or entirely fulvous. 



19b. atriceps atriceps Walsh 



19a. Exochus atriceps atricorpus, new subspecies 



Blackish. Face, side of frons entirely or with a narrow subdorsal 

 interruption, large subtriangular spot at top of eye (curving a little 

 around hind ocellus and usually continuous with mark on side of 

 frons), cheek, adjacent part of temple, mouth parts, under side of 

 scape, upper margin of pronotum, tegula, subtegular ridge, and 

 usually a spot on upper part of prepectus, ivory; front coxa broadly, 

 middle coxa moderately, and hind coxa narrowly whitish apically, 

 the rest of the coxae fulvous to brown; front and middle trochanters 

 ivory, fulvous above; femora fulvous, the front and middle femora 

 whitish apically and the hind femur infuscate at apex; basal 0.2 of 

 tibiae whitish, the rest of the tibiae fulvous to brown; tarsi brown, 



Figures 123, 124. — Localities, subspecies of Exochus atriceps: 123 (left), atricorpus; 



124 (right), atriceps. 



