Revision of the Nearctic species of Acanthocnema Becker, 1894 (Diptera: Scathophagidae)

The Nearctic species of Acanthocnema Becker, 1894 are revised, including the description of three new species: A. albibarba (Loew, 1869), A. capillata (Loew, 1872), A. nigrimana (Zetterstedt, 1846), A. pulchripennis sp. nov., A. rainierensis sp. nov., A. ruficauda Curran, 1929 and A. torrenticola sp. nov. Acanthocnema nigrimana is newly confirmed from North America. All species are illustrated, distributions mapped and an identification key to species is presented. The larval cephaloskeleton and puparium of A. torrenticola sp. nov. are briefly described and illustrated and the puparium of A. albibarba is illustrated.