Whether the Salticellinae and the group around Sepedon warrant recognition as additional subfamilies or are better included in the Sciomyzinae proper is likewise not yet entirely clear.

Sciomyzidae are small or medium-sized (2–14 mm), usually slender flies with predominantly dull grey, brown, reddish or yellow body, rarely black-lustrous.

The antennae are usually elongate and the arista is pubescent or has shorter or longer hairs.

Marsh flies are common along the edges of ponds and rivers, and in marshy areas.

[3] Very little is known about the complete life cycle of these flies but most of the known larvae are semi-aquatic and some are aquatic.

In some terrestrial species the penultimate larval instar emerges from the snail or slug it developed in.