Notonectidae

Commonly called “Back swimmers” because they swim upside down. Similar in appearance to the “Water boatman” but larger in size (up to 20 mm). Backswimmers swim on their backs, vigorously paddling with their long, hair-fringed hind legs and attack prey as large as tadpoles and small fish. They can inflict a painful “bite” on a human being (actually, similar to a mosquito “bite”, it is a stab with their tubular mouthpart). They inhabit still freshwater, e.g. lakes, ponds, marshes, and are sometimes found in garden ponds. Although primarily aquatic, the adult stage can fly and will do so to disperse to new habitats.