Length 4 to 7 mm. The black stigma is clear cut, contrasting with costal cell in both sexes. Hairs on abdomen of the male are long and all black, in the female the hairs are short and pale. Antennal flagellum 7-segmented. Body of both sexes black. Female legs are ochreous. Males have black femora but with the hind tibia and tarsi brown. The male hind basitarsus (first segment) is slightly swollen, about three times as long as wide which is diagnostic for this species.

Grassland and well vegetated areas and hedgerows and also over water.

March to June.

Breeds in soil and sometimes seen in swarms.

Fairly frequent and widespread in England and Wales.

Fairly frequent in Leicestershire and Rutland.