Burrowing water beetles. Formerly considered to be in the Dytiscidae. Adults have a tapered oval shape; notopleural suture present; first ventrite divided by hind coxae; large hind trochanters; antennal segments 3-11 filiform and much longer than segments 1+2; visible scutellum lacking; sternum raised, platform-like; moderately to well-developed protibial spur; protibia fits into groove of profemur.

Larvae with 6-segmented legs, two apical claws; 8 abdominal segments; urogomphi short; body cylindrical or spindle-shaped, well scleritized.