Marsh fly

Marsh flies are generally slender, yellowish or brownish, about 0.25-0.5 inches long. They have fairly prominent eyes, prominent forward-pointing antennae, and bristles on the hind femora (upper hind leg). The wings are often mottled with various light brown markings according to species.
Marsh flies are common along the edges of ponds and rivers, and in marshy areas. The adults drink dew and nectar. The larvae prey on or become parasites of Gastropoda (slugs and snails). Very little is known about the complete life cycle of these flies.