THE CANADIAN ENTOMOLOGIST. 419 



and two or three anterior that are short and weak; prescutellar 

 acrostichals present: s^utellar apicals present; three sternopleuraIs : 

 lower sternopleurals consisting of a single row of strong bristles and 

 numerous other irregularly placed bristles anterior to it. 



Abdomen. — Somewhat conical, clothed above with short de- 

 cumbent bristles, beneath with short almost erect hair. Ventral 

 plates, as a whole, with their sides converging posteriorly, the 

 first bearing long erect hairs, vestiture of second and third short 

 and decumbent except at sides and posterior margin, first usually 

 trapezoidal, its sides slightly converging posteriorly. Fourth plate 

 prominent, in profile its base with a large somewhat conical 

 elevation posteriorly, posterior inner edges of lamelhe bent inward 

 and each with a "brush" of very densely S2t, short, stout, blunt 

 spines on proximal half. 



Chcetotaxy. — Second and third segments without marginal 

 bristles, fourth with a complete row ending ventrally at forward 

 turn of margin. 



Genital Segments. — Prominent, dull orange. First, usually 

 concealed to just beyond "humps"; in profile slightly convex; 

 faintly yellowish pollinose dorsally, anterior portion including 

 "humps" sometimes slightly darkened, rarely the entire segment; 

 clothed with short hair, "humps" bare; marginal bristles present, 

 three to five on each side of centre: second, rotund, not flattened; 

 vestiture longer than that of first; anal area of medium size, ex- 

 tending upward at least to centre of posterior surface. Forceps 

 darkened, inner edges of prongs approximated to about the middle 

 then slightly separated; tips blackish, bent forward and slightly 

 spread apart; clothed with short hair nearly to prong tips, longest 

 at sides; base with upward flap-like extensions. 



Genitalia. — Head of penis large, distinctly marked off from 

 base on posterior surface by a narrow band of membrane. 

 Accessory plates hairy. 



( 9 ) Females differ from males in the following important 

 points: 



Head.— Breadth of front at narrowest part slightly greater 

 than eye width. Inner orbits of eye on upper part of front 

 diverging downward. 



