Any of various freshwater aquatic beetles that have a smooth oval body and flattened hind legs adapted for swimming, and that carry an air bubble underneath their abdomens
Any of various aquatic beetles, especially of the family Dytiscidae, having a smooth oval body and flattened and fringed hind legs adapted for swimming
These beetles swim with great agility, the fringed hind legs acting together like oars
Any one of numerous species of aquatic beetles belonging to Dytiscus and allied genera of the family Dytiscidæ, and to various genera of the family Hydrophilidæ
any of numerous aquatic beetles usually having a smooth oval body and flattened hind legs for swimming