Accepted by D. Bickel: 13 Aug. 2008; published: 10 Sep. 2008 1 ZOOTAXA ISSN 1175-5326 (print edition) ISSN 1175-5334 (online edition) Copyright © 2008 · Magnolia Press Zootaxa 1874: 1–15 (2008) www.mapress.com/ zootaxa/ Two new neotropical genera of the shore-fly tribe Ephydrini Zetterstedt (Diptera: Ephydridae) WAYNE N. MATHIS Department of Entomology, PO Box 37012, National Museum of Natural History, MRC 169, Smithsonian Institution, Washington, D.C. 20013-7012, USA. E-mail: mathisw@si.edu Abstract Two new shore-fly genera, Paraephydra gen. nov. and Neoephydra gen. nov., from the Neotropical Region are described. Paraephydra is revised and includes P. freitasi (Oliveira), comb. nov. and P. stauros, sp. nov. For the genus Neoephydra, N. araucaria, sp. nov., is described and new combinations are made for most Neotropical species previ- ously placed in Dimecoenia. The tribe Ephydrini is characterized and a key to the genera of this tribe is presented. Key words: Ephydridae, Ephydrini, Neotropical Region, new genera and two new species Introduction The purposes of this paper are to characterize the tribe Ephydrini, to present a key to the genera, including two new genera from the Neotropical Region, and to describe these new genera. Although I have a more compre- hensive treatment of Neotropical Ephydrini in progress, the names of these two new genera and the resultant new combinations are needed now for inclusion in the forthcoming Manual of Central American Diptera. The first new genus, Paraephydra, is revised more comprehensively, as it only includes two known species. The second new genus, Neoephydra, includes most Neotropical and one Afrotropical species that were described previously in Dimecoenia. These congeners in Neoephydra are made new combinations, but only the type species of this genus, N. araucaria, is described herein. Materials and methods I have generally followed the descriptive format and procedures established in previous papers (Mathis and Simpson 1981). Five head and three venational ratios that are used in the descriptions are defined below (all ratios are based on three specimens - the largest, smallest, and one other). Head Ratio: Head width/head height. Both measurements are maximum distances and are taken from the head in anterior view. Frontal Ratio: Frontal width/frontal length. The width measurement is taken at the level of the anterior ocellus. The length measurement is taken between the level of the posterior ocelli and the anterior margin. Both measurements are maximum distances. Facial Ratio: Facial width/facial height. Facial width is the narrowest distance between the compound eyes. Facial height is the distance between the ptilinal suture and the oral margin, as measured in a straight line between the antennal bases. Both measurements are maximum distances and are measured from the head in anterior view.