These aquatic diving beetles have bodies that are compressed top to bottom and keeled laterally and ventrally. They have hydrodynamic bodies and average 27mm in length.
Range mass: 30 (high) g.
- Crowson, R. 1981. The Biology of the Coleoptera. New York: Academic Press.
- van Nostrand, B. 1972. Grzimeck's Animal Life Encyclopedia: Insecta. New York: Reinnold Company.