Subfamily
Psepheninae
Psephenus falli. Photo: (c) Kim Cabrera, some rights reserved (CC BY-NC-ND)
Water-penny beetles are a family (the Psephenidae) of 272 species (in 35 genera) of aquatic beetles found on all continents, in both tropical and temperate areas. The young, which live in water, resemble tiny pennies. The larvae feed – usually nocturnally – on algae on rock surfaces. The presence of water penny larvae in a stream can be used as a test for the quality of the water, as they are pollution-sensitive. They cannot live in…