Notes on Megalotomus Fieber, 1860 in the Palaearctic Region (Hemiptera, Heteroptera, Alydidae) Author Yi, Wenbo Department of Biology, Xinzhou Teachers University, Xinzhou 034000, China Author Wang, Shijun School of Plant Protection, Shanxi Agriculture University, Taigu 030800, China Author Zhang, Hufang Department of Biology, Xinzhou Teachers University, Xinzhou 034000, China Author Bu, Wenjun Institute of Entomology, Nankai University, Tianjin 300071, China text Zootaxa 2022 2022-04-20 5128 2 211 224 journal article 55848 10.11646/zootaxa.5128.2.3 7b070c6a-fd3e-40b6-b8b2-f38d09aa9360 1175-5326 6479798 64977C0C-5A79-47C5-96BF-7895D1FFBC7B Genus Megalotomus Fieber, 1860 Megalotomus Fieber, 1860: 58 . Type species by subsequent designation ( Oshanin, 1912: 24 ): Alydus limbatus Herrich-Schaeffer, 1835 (= Cimex junceus Scopoli, 1763 ). Ghauri, 1972: 285–287 ; Hsiao, 1977: 276–277 ; Nonnaizab, et al ., 1986: 305–313; Moulet, 1995: 272–273 ; Liu & Liu, 1998: 41–43 ; Dolling, 2006: 38 . Huphus Mulsant & Rey, 1870: 157–158 (Synonymized by Puton, 1872: 311 ). Type species by subsequent designation ( Kerzhner, 2003: 103 ): Alydus sareptanus Baerensprung, 1859 (= Alydus ornaticeps Stål, 1858 ). Diagnosis. Megalotomus differs from other genera of the family Alydidae by the combination of the following characters: body slender, small to large sized, body length range 10.0–17.0 mm, body colour from yellow to black; head almost triangular, slightly narrower than pronotum; antennal segment I longer than or equal length to segment II; posterior angles of pronotum prominent, slightly raised, always pointed; femur and tibiae straight with no curving, tibiae longer than femur, femora with 3–8 spines, inner surface with plectrum; genital capsule with a pair of surcapsular spines, never crossing over, parameres elongate, slender and curved; posterior margin of female abdominal sternite VII split longitudinally in middle [valid only if specimens of female Megalotomus quinquespinosus (Say, 1825) are examined and confirmed]. Distribution and diversity. This genus is distributed in the Palaearctic and Nearctic Regions, and according to the literature ( Dolling 2006 ) and the results presented herein contains eight species: Megalotomus junceus ( Scopoli, 1763 ) ; Megalotomus quinquespinosus (Say, 1825) ; Megalotomus ornaticeps ( Stål, 1858 ) ; Megalotomus costalis Stål, 1873 ; Megalotomus castaneus Reuter, 1888 ; Megalotomus angulus ( Hsiao, 1965 ) ; Megalotomus zaitzevi Kerzhner, 1972 ; Megalotomus acutulus Liu & Liu, 1998 . Among these, seven species occur in the Palaearctic Region, with only M. quinquespinosus (Say, 1825) recorded from the Nearctic Region. A new combination transferred from Alydus to Megalotomus and a new junior synonym are proposed below.