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NORTH AMERICAN DIPTERA 



Family Borboridae 



Rather small to very small, usually l)laek or brown flies. 



Head hemispherical, the face rather perpendicular, concave or 

 somewhat retreating; oral vibrissce present; front broad, usually with 

 l)ristles. Antennse short, rounded or oval, with dorsal, ])ubescent or 

 bare arista. Wings rarely absent; auxiliary vein incomplete or prac- 

 tically absent; second basal and anal cells often incomplete or absent. 

 Legs of moderate length, the femora strong; basal segment of the 

 posterior tarsi short and usually dilated. 



The Borborids are almost always found about decomposing organic 

 matter, in swami)y places and about excrement. 



The larvie of Borhorus live in excrement and refuse and are 

 cylindrical, their skin roughened by minute bristles; antenna two seg- 

 mented; mouth hooks well developed; posterior segment with a conical 

 protuberance and smaller tubercles about the spiracles. In Limosina 

 the posterior spiracles are tube-like and the larvae are found in fungi, 

 algffi, etc. 



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Borboridse. — 1, Sphserocera; 2, 3, 4, Leptocera; .", 6. 7, Borborus ; S, Scatophora. 



