Description of two new species of Oecetis (Trichoptera, Leptoceridae) from Borneo Author Johanson, Kjell Arne F2A38CF6-59EB-4F88-BFEB-761DBEA7B01A Department of Zoology, Swedish Museum of Natural History, Box 50007, 10405 Stockholm, Sweden. kjell.arne.johanson@nrm.se Author Malm, Tobias 4CD5E640-D2F2-4123-913E-E854959424EA Department of Zoology, Swedish Museum of Natural History, Box 50007, 10405 Stockholm, Sweden. tobias.malm@nrm.se Author Sjöberg, Tin F20B3A9C-7173-409D-8C89-92977B6D2B8D Department of Zoology, Swedish Museum of Natural History, Box 50007, 10405 Stockholm, Sweden. tin.sjoberg@nrm.se text European Journal of Taxonomy 2022 2022-05-18 819 158 165 journal article 55464 10.5852/ejt.2022.819.1787 0f6a0aa7-3aaa-4d95-a674-2327ec91945a 2118-9773 6564531 80DE5F71-8A1C-472F-9205-F956639D0605 Oecetis apelqvisti sp. nov. urn:lsid:zoobank.org:act: 0463DEDE-CF3B-43BA-9B3D-AF23699C165C Figs 6–11 Diagnosis The species is distinguished from many of the Oriental and Palearctic species by the absence of modified tergites on segment VI–VIII. It resembles O. idas Malicky, 2005 in genitalic features, particularly the long and slightly curving superior appendages, long and strongly ventrally curving tergum X, with right branch longer than left branch, and long pair of dorsal processes. Oecetis apelqvisti sp. nov. can be distinguished from O. idas in lateral view by the clearly bifid inferior appendages, and the apical part of phallus with a single hook-shaped sclerotized process. Etymology Apelqvisti , named after one of the collectors, Niklas Apelqvist (formerly Niklas Jönsson). Type material Holotype MALAYSIA • ♂ (in alcohol); Sabah , Tawau , Maliau Basin , Nepenthes Camp , 150 m from Jalan Babi ; 4°43′56.1″ N , 116°52′52.0″ E ; 1031 m a.s.l. ; 13 Dec. 2007 ; N. Jönsson , T. Malm and B. Viklund ; light trap , loc# VKBS-2007-47 ; DNA voucher JQ1; NHRS . Figs 6–10. Oecetis apelqvisti sp. nov. , holotype, ♂ (NHRS). 6 . Genitalia, lateral view. 7 . Genitalia, dorsal view. 8 . Genitalia, ventral view. 9 . Phallus, lateral view. 10 . Phallus, ventral view. Scale bar = 0.1 mm. Description of male BODY. Forewing: 6.7 mm (N = 1). Tergites VI–VIII unmodified. GENITALIA ( Figs 6–10 ). Longer than high in lateral view. Segment IX oriented almost vertically, anterior margin uniformly convex along its height; ventral part almost circularly expanded posteriorly; dorsal part reduced. Acrotergite of segment IX well developed, forming single oval aggregation of setal bases about width of dorsal processes combined. Pair of dorsal processes of segment IX elongate, tube-like; segment lacking membranous area. Lower posterolateral plate of segment IX short, high, located from basis of inferior appendages to mid-height of segment; upper posterolateral plate of segment IX lacking. Longitudinal apodeme absent. Tergum X in lateral view twice length of superior appendages, curving ventrally along its length to pointed apex; in dorsal view bilobed from half length, both lobes tapering. Superior appendages very long, tubular, originating at anterior margin of segment IX at junction between dorsal and ventral parts; oriented dorsally before curving posteriorly over segment IX. Each inferior appendage high and wide, about as long as superior appendages, all setae shorter than length of inferior appendages; in lateral view 2-branched, basal two-thirds widening from base, sharply triangular dorsal branch, ventral margin expanded around mid-length; apical branch digitate, narrow, oriented posterodorsally; in ventral view, each inferior appendage with basimesal expansions, sharply narrowing after basal one-third, apical one-third narrow, digitate. Phallus about as long as tergum X in lateral view, uniformly slender, oriented posteriorly before curving ventrally at mid-length, apex with single hook-shaped sclerotized process; in ventral view about length of inferior appendages, tubular, slightly widening apically, hook-shaped sclerotized process located on left side. Distribution The species is only known from the type locality ( Fig. 11 ).