The New World species formerly placed in Borborillus Duda (Sphaeroceridae: Copromyzinae) are transfemdto Norrbomia Papp. These are: N. lacteipennis (Malloch), n. comb., N. fumipennis (Stenhammar), n. comb., N. frigipennis (Spuler), n. comb., N. scripta (Malloch), n. comb., and N. sordida (Zetteretedt). Norrbomia fulvipennis, N. singusta, N. mexicana, N. triglabra, and N. yukonensis are described as new. Borborus articus Malloch is synonymized with N. fumipennis, and Borborus singularis Spuler is synonymized with N. scripta. All ten New World species of Norrbomia are keyed, illustrated and described. Their relationships are discussed and a cladogram is provided. Species in two of the defined clades are kleptoparasitic on dung rolling scarab beetles
