Fallén (1807) and later authors, including Fieber and Douglas & Scott, misidentified Cimex nassatus Fabricius. The species named by them nassatus is Orthotylus marginalis Reuter, 1883. Kirkaldy (1906a: 127) designated nassatus (Fabr.) as type of Orthotylus and marginalis D. & S. as type of Litosoma. The latter designation is invalid, because no such species was included in Litosoma originally; the next was by Van Duzee (1917), who indicated the type species of Litosoma as nassatus Fall. = marginalis Reut.. Later authors indicated marginalis Reut. as the type species of Litosoma (China, 1943; Carvalho, 1952a, 1958b) and either marginalis Reut. (Oshanin, 1912; Stichel, 1935, 1958a) or nassatus F. (China, 1943; Carvalho, 1952a, 1958b; Southwood, 1953; Wagner & Weber, 1964; Wagner, 1974e; Henry & Wheeler, 1988) as the type of Orthotylus. As the type species of Orthotylus and Litosoma was misidentified, a ruling of the International Commission on Zoological Nomenclature is needed.