WATER-BOATMAN, an aquatic hemipterous insect of the family Notonectidae, of which the best-known species (Notonecta glauca) is common in the ponds of Great Britain. The technical name, Notonecta ("back-swimmer"), alludes to the habit of the insect of swimming upside down, the body being propelled through the water by powerful strokes of the hind legs, which are fringed with hair and, when at rest, are extended laterally like a pair of sculls in a boat. This insect is predaceous, feeding on aquatic
larvae or worms. The body is provided with special hairs which serve to retain bubbles of air for respiration when the insect is submerged. The eggs are laid in the stems of water plants.