Pufftails

Sphegina is a genus of small, slender hoverflies. They are widespread throughout Eurasia and North America. In flight they seem to have long hind legs which they often carry hanging down, making them resemble sphecid or ichneumonid wasps. Adult Sphegina are usually found in damp and shady habitats close to water in forested areas, and several species can often be found together. They often feed on white and yellow flowers of Apiaceae, Ranunculaceae, Asteraceae, and Rosaceae like Crataegus, Sorbus, and Sorbaria. Larvae nest in the sap of living and dead trees or in decaying cambium under tree bark lying in water or other damp conditions. The larvae of some species have been discovered in the tunnels of other xylophagous insects.

Sphegina generally have a face strongly concave and bare in both sexes, antennal basoflagellomere oval with a long dorsal and pilose arista; eyes bare and dichoptic in both sexes; postpronotum pilose; metasternum and katepisternum non-pilose; ventral scutellar fringe absent; alula narrow or absent; postmetacoxal bridge complete and broad; metaleg much longer than pro- and mesoleg and with incrassate femur; abdomen petiolate. Sphegina are similar to the species of their sister group Neoascia but are distinguished by the following characters: face oblique, nearly straight, laterally pilose; katepisternum usually pilose; basoflagellomere usually elongate, longer than wide; arista bare and about as long as basoflagellomere.