The family Celyphidae (Diptera, Lauxanioidea) is verified as part of the New World fauna, with a second specimen discovered of a species described from French Guiana in 1844 by P.J.M. Macquart. As this species possesses characteristics that clearly suggest a separate lineage from the Old World celyphids, a new genus is proposed, Atopocelyphus gen. n., with the type species, Celyphus ruficollis Macquart, in the new combination Atopocelyphus ruficollis (Macquart), comb. n. A key to world genera of Celyphidae is presented, along with discussion of generic concepts. Chamaecelyphus Frey is synonymized under Spaniocelyphus Hendel, syn. n., resulting in the following 10 new combinations: Spaniocelyphus africanus (Walker), comb. n.; S. dichrous (Bezzi), comb. n.; S. gutta (Speiser), comb. n.; S. halticinus (Frey), comb. n.; S. kalongensis (Vanschuytbroek), comb. n.; S. ruwenzoriensis (Vanschuytbroek), comb. n.; S. straeleni (Vanschuytbroek), comb. n.; S. upembaensis (Vanschuytbroek), comb. n.; S. violaceus (Vanschuytbroek), comb. n.; S. vrydaghi (Vanschuytbroek), comb. n. The subgenera of Celyphus Dalman are elevated to genus rank, as Paracelyphus Bigot, stat. rev., and Hemiglobus Frey, stat. rev., resulting in the following 17 new and revised combinations: Hemiglobus cheni (Shi), comb. n.; H. eos (Frey), comb. n.; H. lacunosus Frey, comb. rev.; H. pellucidus Frey, comb. rev.; H. planitarsalis (Shi), comb. n.; H. porosus (Tenorio), comb. n.; H. pulchmaculatus (Liu & Yang), comb. n.; H. quadrimaculatus (Tenorio), comb. n.; H. resplendens Frey, comb. rev.; H. rugosus (Tenorio), comb. n.; H. testaceus (Malloch), comb. n.; H. trichoporis (Shi), comb. n.; H. unicolor Frey, comb. rev.; H. violaceus Chen, comb. rev.; Paracelyphus hyacinthus Bigot, comb. rev.; P. medogis (Shi), comb. n.; P. vittalis (Shi), comb. n.
