Clausen (1940) noted this as a separate family of Neuroptera, with only a few species, the adults of which are relatively small. Withycombe (1923) and Killington (1936) gave detailed accounts of Osmylus fulvicephalus Scop. The larvae are amphibious and probe in mud with their long, slender mandibles for Chironomus spp. larvae and other Diptera inhabiting the wet, mossy borders of streams, etc. Eggs are elongate-oval, somewhat flattened, with the chorion bearing reticulate markings. The micropyle is knob-like. They are laid in rows on some object near the water's edge. hatching occurs in ca. 22 days, and larvae mature the following spring. The cocoon is formed in damp moss, and adults emerge 10-12 days after.