(subclass Pterygota, order Coleoptera)
Family of small, yellow, convex water beetles, 2–5 mm long. The hind coxae are expanded into large plates, the legs fringed with swimming hairs. Usually the beetles are found crawling on water plants. The aquatic larvae are noted for the long, fleshy processes of their body segments. Adults and larvae feed mainly on algae. There are 200 species.
Subjects: Zoology and Animal Sciences.