Leptopa filiformis Zetterstedt, 1838

A smallish pale yellow fly with a superficial resemblance to an acalyptrate, such as Lyciella spp., sometimes with brownish patches but without dusting. Unlike all other British members of the family, it lacks long fine hairs on the ventral part of the occiput. Palps short and yellow with a long terminal bristle. Legs entirely pale yellow, tarsi somewhat brownish. Abdomen frequently darkened (after death?) in dry preserved specimens. All strong bristles black. Wing length: ♂ 3.5 - 4.0 - 4.4 mm (13); ♀ 4.0 - 4.7 - 5.2 mm (11).