Creeping water beetles. Most commonly associated with lentic habitats or slow-moving, vegetated sections of streams. Adults have large coxal plates which cover most of the ventral abdominal segments and expose only the tips of the hind femora; notopleural suture present; first ventrite divided by hind coxae, large hind trochanters hidden by coxal plates; body yellowish and most with black spots; legs with swimming hairs; antennae filiform; head narrower than pronotum.

Larvae have 6-segmented legs, with a single claw; elongate, tapering, with 9-10 segments and ending in a long spiny process; well scleritized; EXCEPT for Peltodytes which has multiple, long hair-like gills arising from all the thoracic and abdominal segments.