The marsh beetles. Adults are terrestrial and may be found on emergent vegetation in wetlands or along stream margins. Body oval, soft-bodied; head deflexed; antennae 11-segmented, filiform to subserrate; tarsi all 5-segmented; 4th segment bilobed, larger than 3rd.

Larvae are aquatic and may be found in wetlands, along stream margins or undercut banks, particularly where there is leaf litter and decomposing wood. Larvae roachlike; head prognathus and smaller than pronotum; body segments scleritized and brown. The larvae are unique among all larvae of Coleoptera and the rest of the holometabolous insects in having long, multi-segmented antennae.