|any of various heteropterous insects adapted to living in the water or on its surface, esp any of the family Belostomatidae (giant water bugs), of North America, India, and southern Africa, which have flattened hairy legs|
giant water bug
any wide and flat-bodied aquatic insect of the family Belostomatidae (order Heteroptera). This family, although containing only about 100 species, includes the largest bugs in the order: sometimes exceeding 10 cm (4 inches) in the South American species Lethocerus grandis and ranging between 2 and 5 cm in northern climates. These insects are usually seen suspended in a quiet pond or lake, the tip of their abdomen piercing the water surface and the brown, oval body hanging below.
Learn more about giant water bug with a free trial on Britannica.com.