Taken on 23rd July 2008, Lincoln UK. Length 3.5-4mm. It was walking on a stem of a kidney bean plant.
Beware of similar small orange flies, but this one is quite distinctive.
Showing the black markings on wings.
It can be a winter cereal crop pest with damage in early spring only, but larvae also feed on wild Poa, Agropyron, Phleum, Lolium, & Agrostis grasses.