THE XERCES SOCIETY FOR INVERTEBRATE CONSERVATION

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

Hydrochid beetles typically live near the edges of moving water; in lakes they inhabit wave swept shores and in streams they live at the edges of riffles. They were once considered to be part of the Hydrophilidae, and were only recently given their own family. Like hydrophilid adults, the last five segments of their antennae are swollen to form a club, and the segment before the club is usually cup-shaped. Unlike the hydrophilids, the eyes protrude from the sides of the head. The pronotum is not grooved as it is in the Helophoridae, and t he back edge of the pronotum is clearly narrower than the elytra.

The larvae are also similar to the Hydrophilidae; they both lack filaments on the abdomen, have prominent mandibles, and lack well developed tails or claws on the hind end. However, in hydrochids, the mandibles attach to the head between the antennae instead of outside of the antennae.

The images above are from E. Reitter's 1908 publication.