TriK CANADIAN KNTOMOLOGiST. 127 



frontal vitta slate-black, about one-half width of front ; sides of face and 

 facial depression silvery white, with a brassy lustre; the sides of face with 

 a row of bristles below near the eye-margin ; cheeks silvery, wide, bristly ; 

 vibrissie stout, decussate, inserted on oral margin, facial ridges bare 

 except several short bristles above vibrissfe ; frontal bristles descending 

 to base of third antennal joint, two posterior pairs directed backward, no 

 orbital bristles ; antennae blackish, third joint hardly twice as long as 

 second, moderately wide ; arista concolorous, 3-jointed, thickened on 

 basal third, plumose on basal half or more ; proboscis brownish, almost 

 as long as height of head, stout ; palpi blackish, moderately stout, bristly ; 

 occiput silvery white, covered with black bristles. Thorax silvery white, 

 with three heavy black vittse ; scutellum silvery white, with a subapical 

 divergent pair of macrochaetce, a very weak decussate apical pair of bristles 

 between them, a decussate weak subdiscal pair of bristles, and two lateral 

 pairs of macrochaetae. Abdomen about as wide as thorax, silvery, 

 marbled with gray, with a more or less distinct median dark line ; 

 hypopygium rufous yellow ; first and second segments with a lateral 

 macrochceta ; third with about three lateral, a median marginal pair, and 

 some shorter marginal bristles between ; anal with a marginal row of about 

 twelve. Legs blackish, femora silvery white, tibiie bristly, claws and 

 pulvilli elongate, pulviili smoky black. Wings grayish hyaline, longer 

 than abdomen ; apical cell widely open before tip of wing, fourth vein 

 with wrinkle and slight stump at bend ; apical cross-vein deeply bowed 

 in, hind cross-vein sinuate, nearer to bend of fourth vein ; tegulte nearly 

 white, halteres tawny yellowish. 



9 . Differs as follows : Front nearly or quite one-third width of head, 

 frontal vitta about one-half width of front '; three hind pairs of frontal 

 bristles directed backward, the hindmost pair much the longest and the 

 forward pair of the three much the shortest ; two stout orbital bristles 

 directed strongly forward. The weak decussate apical pair of bristles on 

 scutellum is apparently wanting (there are no scars apparent), the weak 

 subdiscal pair of bristles are not decussate. Abdomen broadened, much 

 wider than thorax, macrochsetae nearly the same ; anus rufous-yellow, 

 fringed with marginal bristles. Claws and pulvilli much shorter. 



Length of body, 7 to 8 mm.; of wing, 6^^ to 7 mm. 



Described from one male and one female, bred by Professor J. M. 

 Aldrich from cocoons of Cimbex Americana. Issued May 30 and June 2. 

 Brookings, So. Dakota. 



