The Phoridae are a family of small, hump-backed flies resembling fruit flies. Phorid flies can often be identified by their method of quickly running across a surface instead of taking flight to escape threats. This behaviour is a source of one of their alternate names, scuttle fly. Another vernacular name, coffin fly, refers to Conicera tibialis. About 4,000 species are known in 230 genera. The most well-known species is cosmopolitan Megaselia scalaris. At 0.4 mm in length, the world's smallest fly is the phorid Euryplatea nanaknihali.
Description
Phorid fly larva are minute or small – 0.4–6 mm (
The head is usually rounded, and in some species narrowed towards the vertex. The vertex is flat. In some species, there is an ocellar protrusion above the surface of the vertex. The eyes are dichoptic. The third segment of the antenna is large and rounded or elongated, and bears a long apical or dorsal arista directed sideways. The arista is glabrous or feathered. The third antennal segment in some species is unique in shape. Sexual dimorphism is often shown in the shape and size of third segment of antennae, and in males, the antennae are usually longer. The proboscis is usually short and sometimes with enlarged labella. The proboscis may be elongated, highly sclerotized, and bent at an angle. Maxillary palpi vary in shape and are sometimes large (species of genus Triphleba).
The groups of bristles are developed on the head. Two pairs of supra-antennal bristles, sometimes one, are completely reduced. Above these are antennal bristles closer to (but still some distance from) the margin of eyes. Three bristles are spaced along the margin of eyes-anterolateral midlateral and posterolateral. Immediately before the ocellar callus are two preocellar bristles. The ocellar callus bears a pair of ocellar bristles and in some genera between the antennae and the preocellar bristles two additional, intermediate bristles occur.
