Very small (1-3 mm) flies, dull brownish gray in color, with slightly fumose wings. Humeral break on costa complete, situated just beyond humeral vein, subcostal vein short and thick, removed from radial vein R1, no break at end of subcosta, lower fronto-orbital setae present but lateroreclinate, never medioclinate, postocellar setae extremely large, divergent, no true vibrissae.