THE XERCES SOCIETY FOR INVERTEBRATE CONSERVATION

Aquatic Invertebrates in Pacific Northwest Freshwater Wetlands
An Identification Guide and Educational Resource

Hydraenidae adults inhabit the shoreline, feeding primarlily on fungi and bacteria. They lay their eggs at the waters edge; larvae feed for about a year on algae and microorganisms among plants in damp margins.

The adults are very small (<2mm) and lack swimming hairs on their legs. The last five segments of their antennae are swollen to form a club, and the segment before the club is usually cup-shaped. The adults are fairly diverse; the palps may be long, and the pronotum can have a variety of textures.

The larvae are very small with ten abdominal segments and two small tails around either side of segment ten. Each tail has two segments and the abdominal segment has a ventral pair of curved hooks. They lack finger-like lobes on any of their abdominal segments.