PROC. BIOL. SOC. WASH. 97(2), 1984, pp. 251-262 A REVISION OF THE SHORE FLY GENUS HOMALOMETOPUS BECKER (DIPTERA: EPHYDRIDAE) Wayne N. Mathis Abstract. — Species of the genus Homalometopus (type-species: H. albiditinctus Becker) are revised and now comprise six species of which four are new: H. castaneus (Israel), H. corfuensis (Greece), H. ibericus (Spain), H. lukinatcha (Sen-egal). One species, H. platycephalus (Becker, new combination, Tunisia, previ-ously a synonym of H. albiditinctus), is resurrected from synonymy. Homalo-metopus is an Old World genus with a primarily circum-Mediterranean distribution but with extensions along the coast of West Africa (Senegal) and along the Red Sea (Gulf of Aqaba). The genus is halophilous, occurring mostly in coastal areas but also inland, where saline conditions exist. While conducting field work in Israel for a faunal study of the Ephydridae of the Middle East (Fauna Palestina Series), two species of the genus Homalometopus Becker were collected. Becker (1926) treated only one species in the most recent revision of the genus, and I became interested in discovering if that species were represented by any of the specimens from Israel. The present study developed from that research. Homalometopus, with H. albiditinctus Becker as type-species, was described early in this century (Becker 1903) from specimens collected at Port Said, Egypt. Since then, the genus has received meager attention. In 1907 Becker described a related genus and species from specimens collected in Tunisia, which he appro-priately named Tunisia platycephala. Later, however, Becker (1926) considered that species to be conspecific with H. albiditinctus. Several years afterward, Collin ( 1 949) published an excellent diagnosis for Homalometopus and also pointed out inaccuracies in the illustrations and text of Becker (1926). Collin's only lapse was his statement that no prescutellar bristles, except the dorsocentrals, are present. The lapse resulted from not having access to species of the genus other than H. albidinctus, the only species of Homalometopus lacking these bristles. After Collin, no further taxonomic work has appeared on the genus. Beyond taxonomic works, there are a few publications providing new distribu-tional data for the genus. In each case, however, the authors failed to recognize that they were dealing with mostly undescribed species, which were misidentified as H. albiditinctus. Czerny and Strobl (1909) reported H. albiditinctus (=H. ibe-ricus, new species) from the Mediterranean coast of Spain; Soika (1956), in a study of animal populations of the Sahara, published a distributional map of H. albiditinctus (=four species), outlining its circum-Mediterranean distribution; and Canzoneri (1981) reported the occurrence of//, albiditinctus (=//. lukinatcha, new species) from Senegal. The descriptive terminology used here follows that published in the recent Manual of Nearctic Diptera, Vol. 1 (McAlpine 1981) with one exception. I have followed Sabrosky (in press) in using "microtomentum ,, rather than pruinescence
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