200 PROG. ENT. SOC. WASH., VOL. 20, NO. 9, DEC., 1918 



Q. 3rd joint of antenna longer and more 

 slender, basal process slightly falcate; 

 antennae wholly pale; abdomen abruptly 

 narrowed from base, dark reddish 

 brown, somewhat shining, with narrow 

 triangles recedens 



QQ. 3rd joint of antenna not so slender, basal 

 process not falcate; basal joints and 

 tip of third joint dark; abdomen not 

 as above. 



R. Dividing line between coarse and fine 

 facets of eye of male high, leaving 

 an almost semicircular portion of 

 eye below it; wings brownish at 

 base and along veins, but the in- 

 terior of cells grayish-white, .sulcifrons 



RR. Dividing line not so high, portion 

 of eye below it broadly sigmoid; 

 wings similar to those of last species, 

 but interior of cells not so whitish. 



abdominalis 



PP. Abdomen blackish-brown or black. 



S.^Triangles ending abruptly on 4th segment, 

 never more than faintly indicated on 

 5th and 6th; thorax mostly black; 



wings blackish trispilus 



SS. Triangles on all abdominal segments. 

 T. Triangles distinctly larger on seg- 

 ments 3 to 5, very small on 2; scutel- 

 lum densely white pollinose. . . .molestus 

 TT. Triangle on segment 2 large. 



U. Tibiae chiefly gray, length over 



15 mm .. melanocerus 



UU. Tibiae chiefly blackish, length 



under 15 mm coffealus 



OO. Posterior margins of abdominal segments not 

 pale. 



V Thorax and scutellum chiefly livid gray; ab- 

 domen blackish; wings smoky. . . super jumentarius 

 VV. Thorax, scutellum and abdomen brownish. . .acteon 

 MM. The pale markings form 2 or 3 longitudinal rows of 



triangles or spots. 

 W. Upper angle of 3rd antennal joint drawn out in a long 



process. hirtioculatus 



WW. Upper angle of 3rd antennal joint not so produced. 



