Geir e. e. soli Museum of Zoology, University of Bergen CHALASTONEPSIA ORIENTALIS GEN. N., SP. N., A SECOND GENUS IN THE TRIBE METANEPSIINI (DIPTERA, MYCETOPHILIDAE) Soli, G. E. E., 1996. Chalastonepsia orientalis gen. n., sp. n., a second genus in the tribe Metanepsiini (Diptera, Mycetophilidae). -Tijdschrift voor Entomologie 139: 79-83, figs. 1-8. [ISSN 0040-7496]. Published 15 October 1996. The genus Chalastonepsia is erected for a new species from Malaysia, C. orientalis. The genus has numerous characters in common with Metanepsia Edwards, and the two are likely sister-groups. The new genus differs most markedly from Metanepsia in having a complete radial sec-tor, a well developed Sc, and a relatively short stem of the median fork; further, the male ter-minalia are very different in the two genera. Awaiting a phylogenetic analysis of the family the tribe Metanepsiini is maintained, and an emended diagnosis is given in order to include Chalastonepsia. The sistergroup of the tribe is likely to be found among genera in the tribe Gnoristini. Geir E. E. Soli, Present address: Zoological Museum, Sars gate 1, N-0562 Oslo, Norway. Key words. — Mycetophilidae, Metanepsiini, new genus, new species, Malaysia. The Metanepsiini is usually regarded to represent one of five tribes in the subfamily Sciophilinae in the family Mycetophilidae (e.g. Matile 1971, Hutson et al. 1980, Vockeroth 1981). Some authors, however, pre-fer to rank these tribes at the level of subfamilies (e. g. Tuomikoski 1966, Hennig 1973, Väisänen 1984, 1986, Matile 1989). Metanepsiini hitherto included a single genus, Metanepsia Edwards, 1927, erected for the Javanese species, M. javana Edwards, 1927. Later seven more species were described from the Afrotropical region (Matile 1971, 1972, 1975, 1980). In the collection of the Natural History Museum in London a peculiar looking specimen was found among the pinned, unidentified Oriental material of Mycetophilidae. The specimen, a male, had long-stalked, strongly setose flagellomeres, and reduced mouthparts. The species must be attributed to the tribe Metanepsiini, but could not be ascribed to the genus Metanepsia. Methods and terminology The pinned specimen was cleared and slide mount-ed in Canada balsam. In addition, slide mounted ma-terial of three Afrotropical species of Metanepsia was studied. The terminology used in the description fol-lows Vockeroth (1981) and McAlpine (1981). Chalastonepsia gen. n. Type species. -Chalastonepsia orientalis sp. n., by present designation. Diagnostic characters. -Reduced mouthparts, one-segmented palpus and bead-like flagellum, each flagellomere bulbous with a long stalk-like apical por-tion, basal part with numerous long setae. Etymology. -From Greek, chalaston, a chain, re-ferring to the outlining of the male flagellum, and Metanepsia, a related genus. Description Head. -Antennae inserted below middle of head. Scape and pedicel with numerous small, erect setae. Fourteen flagellomeres, 1-13 with bulbous basal part with circle of very long curved setae and distinctly prolonged, stalk-like apical part; last flagellomere conical. Three ocelli, of equal size, situated along straight transverse line. Lateral ocelli well separated from eye margin. Eyes large, median margin evenly rounded with very shallow incision above antenna! socket. Eyes with few small hair-like setae. Back of head with numerous, evenly dispersed setae. Postgenae well developed, with median convexity be-low occipital foramen. Frons with broad suture be-tween median ocellus and frontal tubercle. Frontal tubercle distinct, bilobate. Face subquadrate, shorter than wide, setose. Clypeus rounded, bare. Cibarial pump well developed. Prementum strongly reduced. Labrum not traceable. Labella small. Stipes weak, ap-parently fused, bare. Lacinia absent. Palpi strongly re-duced, only one visible segment, palpomere 3, with some erect setae, and distinct sensory pit, forming a hollow depression dorsally. 79
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