116 THE BLOowFutsts of NortH AMERICA 
proclinate and one small reclinate in female; vertex small; ocellar 
bristles proclinate, weak in male, nearly divaricate in female; 
postocellar bristles proclinate, weak; clypeus twice as long as 
wide, deeply sunken, narrow; facial carina absent; parafaciale 
narrowed above, bare; faciale rounded and with two or three 
rows of very short black setae which ascend almost two-thirds 
the distance to the antennal base; vibrissa slightly above the 
oral margin; proboscis about half head height; palpus cylindrical 
and clubbed at tip in male, clavate in female; antenna at or but 
slightly below eye middle when head is viewed in profile, the 
bases approximated; third segment reaching fully four-fifths the 
distance to vibrissa; arista long plumose above, shorter below for 
four-fifths the distance to the apex; back of head concave above 
and rounded below in profile, with one row of postocular cilia. 
Thorax with three humeral bristles of medium size; propleural 
bristles strong; preintraalar bristles two, weak, the middle 
bristle absent; preacrostichal bristles absent or vestigial; pre- 
dorsocentral bristles two, weak; posthumeral bristle absent; pre- 
supraalar bristle one, strong; sternopleural bristles two; hypo- 
pleural bristles usually arranged in ‘‘V’’ along posterior and 
dorsal margin of the sclerite; pteropleuron bare on anterior half, 
thickly covered with black setae on posterior half; prosternum 
large, wide, setose; postalar declivity with tuft of setae in center; 
tympanic pit setose; postacrostichal row represented by one large 
prescutellar bristle; postdorsocentral bristles strong only in pre- 
scutellars but sometimes with three or four in the row, all weak; 
intrapostsutural bristle absent; postintraalar bristles two; intra- 
postsupraalar bristles absent; intrapostalar bristles absent; 
mesospiracular bristle one, large; thoracic spiracles large, ovate; 
scutellum with one large and often with two or three smaller 
discal bristles, one sometimes simulating subapical bristle; 
lateral bristles three, strong. 
Coxae with thin pile, the hind coxae sometimes almost bare 
posteriorly; anterior femur with a partial posteroventral row of 
bristles which extends from the middle to the apex; anterior 
tibia with about three dorsal bristles, one near basal third, one 
near middle, and one near apical third, and with one posteroven- 
tral bristle between middle and apical third; middle femur with 
one anterior bristle near middle, one long anteroventral bristle 
near basal sixth, three long posteroventral bristles basally, and a 
close-set row of smaller posteroventral bristles extending from 
near middle to apex; middle tibia with one anterodorsal bristle 
near apical third, one ventral bristle near apical third, two 
posterior bristles, one near basal third and one near apical third, 
