THE CANADIAN ENTOMOLOGIST 423 



sutural dorsocentrals weak but at least as long as those before the 

 suture, only last two pairs strong; nota of abdomen clothed with 

 short, reclinate bristles above, beneath with more erect hairs or 

 bristles; genital segments protuberant, somewhat cone-shaped, 

 visible from above; the two broad lateral lips of the first genital 

 segment dull orange, sometimes slightly darkened, spiracles close 

 to anterior margins; fifth and sixth ventral plates fused; sixth fully 

 exposed, not overlapped by lips of first segment, narrowed pos- 

 teriorly, its posterior margin with bristles on each side of centre. 



Length. — 8.5 to 15 mm., average 12 to 14 mm. 



cf . — Head. — Viewed from side, parafrontals and genae with 

 dark reflections. Breadth of front varies from slightly less to 

 slightly greater than one-half eye width; cheek height approximate- 

 ly one-third or three-sevenths that of eye. Front prominent, sides 

 of frontal vitta parallel or slightly convergent backward. Second 

 antennal segment dark; third about twice length of second; arista 

 plumose to beyond middle. Back of head somewhat convex, 

 usually with four, sometimes three, irregular rows of black cilia 

 behind eyes, otherwise clothed with whitish or yellowish hair that 

 completely covers the metacephalon except that occasionally 

 there are black hairs in lower anterior corners. Cheeks clothed 

 with black hair. Gena with short row of long, sometimes bristly 

 hairs near lower eye orbit, other shorter ones may continue upward. 

 Palpi dark. 



Chcetotaxy. — Lateral verticals absent, rarely weakly developed; 

 vibrissa? inserted slightly above mouth margin. 



Thorax. — Metanotum clothed with slender, reclinate bristles 

 or with bristle-like hair. Hairs covering anterior spiracle dark 

 brown basally, lighter toward tips; those of anterior margin of 

 posterior spiracle dark brown; those of spiracular cover dark brown 

 or brownish, tips yellowish. Epaulets dark. 



Wings. — Bend of fourth vein either an acute, right, or slightly 

 obtuse angle; anterior cross- vein more basal than end of first longi- 

 tudinal; third vein bristly; costal spine vestigial; section HI of 

 costa about one and one-half times section V or even longer; pos- 

 terior margin of alulae either bare or fringed with hair; calypters 

 whitish, fringe of hairs dark at fold, otherwise whitish. 



Legs. — Dark. Posterior trochanter without "brush;" femur 



