Long-toed water beetles. Adults found in streams, mainly in leaf packs or log jams. Elongate, oval; ranging in size from 4-8 mm; head usually retracted into pronotum; antennae short and usually retracted, 11-segmented but with 2nd segment ear-like and covering remaining segments, which are usually broader than long; 5 visible abdominal sternites.

Larvae are terrestrial; elongate, subcylindrical; 9 abdominal segments; pleural sclerites absent or not well developed; retractile gills absent; operculum present; legs 4- or 5-segmented.