Hebecnema umbratica

See Morphology of Diptera for terms. Eyes densely long· (male) or short- (female) haired. The abdomen, seen from behind, with (male) rather dense grey dusting and a sharply defined narrow median dark line, or (female) with thin dusting and a broader, less sharply defined dark median area and faint shifting dark spots. The female thorax, seen from in front, with 4 faint but more or less distinct darker stripes; frontal triangle, seen from slightly behind, usually extending almost to lunule. 3.5–6 mm.