Size 7-8mm. This hump-backed fly has a blackish head, legs and thorax with a somewhat greyer abdomen. The wings are shaded brown.

Vein 3 is unforked, the hind tibia has a pallisade of hairs and it has a broad, elevated ocellar triangle platform.

Various habitats.

Peak time is summer.

This species is a parasite Bibio marci and may also parasitise honey bees, laying eggs on the larvae.

Status in Britain is difficult to determine due to lack of records.

Status in Leicestershire and Rutland not known.