A taxonomic revision of the genus Dichoxenus Horn, 1876 (Coleoptera: Curculionidae: Entiminae: Byrsopagini).

The genus Dichoxenus Horn, 1876 is revised with 25 species, including 17 new species as follows: Dichoxenuscharlesi Anderson, new species (Mexico, Nuevo León), Dichoxenuschiapaneca Anderson, new species (Mexico, Chiapas), Dichoxenus conejo Anderson, new species (Mexico, Veracruz), Dichoxenuscupreus Anderson, new species (U.S.A., Texas), Dichoxenushowdenorum Anderson, new species (Mexico, Nuevo León), Dichoxenusjonesi Anderson, new species (Mexico, Querétaro), Dichoxenusloisae Anderson, new species (Mexico, Nuevo León), Dichoxenusmanzanae Anderson, new species (Mexico, Coahuila), Dichoxenusmcclevei Anderson, new species (U.S.A., Arizona), Dichoxenusreddelli Anderson, new species (U.S.A., Texas), Dichoxenussandersi Anderson, new species (U.S.A., Texas), Dichoxenusschwartzi Anderson, new species (U.S.A., Texas), Dichoxenussculpturatus Anderson, new species (Mexico, Nuevo León), Dichoxenus spatulirostris Anderson, new species (U.S.A., Alabama), Dichoxenussulcirostris Anderson, new species (U.S.A., Texas), Dichoxenussulcithorax Anderson, new species (U.S.A., Arizona) and Dichoxenustamaulipensis Anderson, new species (Mexico, Tamaulipas). Anametis Horn, 1876 is here considered a new junior subjective synonym of Dichoxenus and the following are proposed as new combinations: Dichoxenus granulatus (Say, 1832), Dichoxenus griseus (Horn, 1876), and Dichoxenus subfuscus (Fall, 1907). Amphideeslongulus Sharp, 1891 is transferred to Dichoxenus as Dichoxenuslongulus (Sharp, 1891), new combination. Anametis setosus Blatchley, 1916 and Dichoxenus setiger arkansasensis Sleeper, 1956 are new junior subjective synonyms of Dichoxenus granulatus (Say, 1832). Lectotypes are designated for Amphidees longulus Sharp, 1891, Barynotus granulatus Say, 1832 and Anametisgrisea Horn, 1876. Most species of Dichoxenus are collected on vegetation, especially at night, but some have been collected in leaf litter and three species are suspected or known only from caves. One of these species, D. sandersi, shows more extreme character states typical of cave life, such as reduced pigmentation, long slender appendages and reduced eye size. A key to the 25 species of Dichoxenus as well as habitus images and images of male genitalia are presented to facilitate identification. All distributions are mapped. A key is also given to the genera of Byrsopagini of North America lacking a metanepisternal suture.