Corixidae

Corixidae is a family of aquatic insects in the order Hemiptera, found worldwide in virtually any freshwater habitat, with a few species living in saline water. There are about 500 known species in 55 genera, including the genus Sigara. Members are commonly called lesser water boatmen, the British term that separates species such as Corixa punctata from the greater water boatman Notonecta glauca of the family Notonectidae. The body is long and flattened, 2.5 to 15 millimetres in length, and the oar shaped, hair covered forelegs and scoop shaped tarsi on the hind legs give the group its name; unlike backswimmers they swim right side up. Corixids forage mainly on the bottom, feeding on algae, protozoa and small aquatic organisms, and the feeding style varies from detritivorous and herbivorous to omnivorous or fully carnivorous in the subfamily Cymatiainae. Many genera attract mates by stridulation.