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(Gyrinidae), a family of insects of the order Coleóptera. The bodies are dark and lustrous. The midlegs and back legs are shaped like broad oars; the forelegs are used for grasping.
Whirligig beeties live in reservoirs and circle on the surface of the water (hence the name) and often dive. The eyes of the whirligig are divided into two halves; the lower half serves for underwater vision and the upper for vision in the air. There are about 500 species, some of which are found in the USSR. These beetles are predators, feeding on small aquatic worms, centipedes, and the larvae of malarial mosquitoes (for which reason they are beneficial). The larvae of whirligigs live in silt and pupate on the shore.