Sepedon sphegea is a Palearctic[1] species of fly in the family Sciomyzidae, the marsh flies or snail-killing flies.

[2][3][4] The larva feeds on aquatic snails and as an opportunist on other invertebrates.

[5][6] The habitat of this species includes among many others, pond margins and damp meadows.

It has a particular fondness for Iris pseudacorus which grow at the edges of the pond.

Adults can be found all year long but the main flight period is from March to October.