[3][4] These small stoneflies can reach a length of 5–13 mm (0.20–0.51 in), but most of the species are less than 1 centimeter long.

The wings are slender and cylindrical, usually dark brown in color.

The adults develop in early spring, swarm, mate, and lay the eggs in the water.

The slender, yellowish larvae are herbivorous, feeding on plants and organic waste.

[citation needed] The species of Leuctridae have a mainly Holarctic distribution.