Family NEPIDAE Latreille, 1802 - water scorpions, water stick insects
The family contains 14 genera and about 230 species, distributed world-wide. Species of various genera are predaceous generalists, mostly sit-and-wait predators, feeding on amphipods, arthropods, small fishes, and any other creature they can grasp and subdue. Most species live in lentic habitats or the quiet parts of streams, but some species are largely restricted to lotic habitats. An eyeless Nepa species known only from a Romanian cave is the first troglobitic aquatic hemipteran. Death feigning in nepids is well-known. They overwinter as adults, and eggs are laid in plants or mud banks. Most species have five nymphal instars, but the American Nepa species has four. Most Nepa are flightless, with reduced flight muscles, however some do disperse by flight, as do the other genera. Laccotrephes are strong fliers.
World catalogue: none. World overview: Menke, 1979; Sites & J.T Polhemus, 1994. Palaearctic catalogue: J.T. Polhemus, 1995b. Monographs: Ferrari, 1888 (outdated); Lansbury, 1967 (morphology), 1974a (higher class.); Menke & Stange, 1964 (higher class.). Faunal reviews: Africa - Poisson, 1965a; Asia - Lundblad, 1933a. Biology: Hinton, 1962 (eggs).