A new genus and species of trichobiine bat flies (Diptera: Hippoboscoidea: Streblidae) from Costa Rica CARL W. DICK and RUPERT L. WENZEL Insect Syst.Evol. Dick, C.W. & Wenzel, R.L.: A new genus and species of trichobiine bat flies (Dlptera: Hippoboscoidea: Streblldae) from Costa Rica. Insect Syst. Evol. 37: 433-442. Copenhagen, December, 2006. ISSN 1399-560X. A new genus and species of parasitic bat fly, Megistapophysis mordux gen. n., sp. n., is diag- nosed and described within the subfamily Trichobiinae (Diptera: Hippoboscoidea: Streblidae). Illustrations of the wing, habitus, and male genitalia are provided. The new genus has affini- ties to species of Megistopoda Macquart, 1852, Neotrichobius Wenzel & Aitken, 1966, Paratrichobius Costa Lima, 1921, and the Trichobius phyllostomae group of species. Morphological affinities of related taxa to the new genus are discussed, and information regarding ecology and host associations is presented. The new genus is known exclusively from Costa Rican Sturnira mordax (Goodwin, 1938) (Chiroptera: Phyllostomidae: Stenodermatinae). C. W. Dick, and R. L. Wenzel*, Department of Zoology, Field Museum of Natural History, 1400 South Lake Shore Drive, Chicago, Illinois, 60605, USA (cdick@fieldmuseum.org) *Deceased, 7 July 2006 Introduction Trichobiine streblids are relatively well-known hippoboscoid flies (Wenzel et al. 1966; Wenzel 1970, 1976, Wenzel & Peterson 1987; Guerrero 1993, 1994a, 1994b, 1995a, 1995b, 1996, 1997; Miller & Tschapka 2001). Geographic distribution of the family Streblidae is cosmopolitan, but spe- cies richness peaks in tropical regions, particular- ly the Neotropics (Wenzel 1970). All streblids are obligate, blood-feeding ectoparasites of bats. The 155 species known from the Western Hemisphere have been placed into 25 genera and three subfam- ilies: Streblinae Speiser, 1900, Trichobiinae Job- ling, 1936, and Nycterophiliinae Wenzel, 1966. The form considered herein was recognized as a new taxon by the second author in the 1980s, who identified specimens as an undescribed species of Megistopoda Macquart, 1852 (Timm & al. 1989; Matson & McCarthy 2004). Our further study re- vealed characteristics that justify generic status for the taxon (see Description, new genus). We de- scribe a new genus and species of trichobiine bat flies possessing morphological similarities with species of Megistopoda, Neotrichobius Wenzel & Aitken, 1966, Paratrichobius Costa Lima, 1921, and the Trichobius phyllostomae species group (sensu Wenzel et al. 1966). The new genus is known only from Costa Rica, where it parasitizes the Talamancan Yellow-shouldered Bat, Sturnira mordax (Goodwin, 1938). Materials Adult flies were collected in Costa Rica by captur- ing host bats in mist nets and removing the flies from the bats. Arthropods were preserved in vials of 70% ethanol. Bats were killed and prepared as standard mammalian museum specimens. Mor- phological terminology follows Wenzel (1976). The following abbreviations are used for the institutions cited in this paper: Carnegie Museum of Natural History, Philadelphia, Pennsylvania, USA (CM); Museu de Zoologia, Universidade de Siio Paulo, S5o Paulo, Brazil (MZUSP); Field Mu- seum of Natural History, Chicago, Illinois, USA (FMNH); University of Kansas Natural History Museum, Lawrence, Kansas, USA (KU), Los Angeles County Museum of Natural History, Los Angeles, California, USA (LACM), Museo Na- cional de Costa Rica, San JosC, Costa Rica O Insect Systematics & E~olution (Group 6)