XXXI. FAMILY SYRPHID^B. 



97. Eristcitis tena.r. 



Enlarged one-half. 



After Kellogg. 



Small to rather large flies. Head 

 hemispherical, often elongated or 

 produced in the lower part; as broad 

 or a little broader than the thorax. 

 Face moderately broad, bare or cloth- 

 ed with dust or short pile ; excavated 

 in profile under the antennae and 

 projecting below, or with a distinct 

 convexity near the middle part, nev- 

 er with longitudinal furrows or lat- 

 eral ridges, usually convex trans- 

 versely, sometimes with a median ridge. Oral opening 

 large; proboscis rarely much elongated. Front never 

 excavated. Antennae usually porrect and approximated 

 at their base, three-jointed, usually with a dorsal arista. 

 Eyes large, bare or pilose; in the male usually contigu- 

 ous above. Ocelli always present. Thorax compara- 

 tively large and robust, moderately arched above. Squa- 

 mae of moderate size. Abdomen composed of five or six 

 visible segments, rarely with only four. Hypopygium 

 usually not prominent. Legs usually of moderate 

 strength, never long. Bristles rarely present in any part 

 of the body, never on the head; the body generally thinly 

 pilose or bare, but sometimes clothed with thick pile. 

 Wings comparativelylarge; third longitudinal vein never 

 forked; marginal cell open or closed; the fourth vein 

 terminates in the third at or before its tip ; three poste- 

 rior cells; basal cells large; anal cell always closed be- 

 fore the border of the wing ; between the third and fourth 

 longitudinal vein and nearly parallel with them, a false 



246 



