Four new species of caddisflies (Trichoptera: Polycentropodidae, Psychomyiidae Hydropsychidae, Odontoceridae) from Khao Nan and Tai Rom Yen National Parks, southern Thailand Author Suwannarat, Nannaphat Author Malicky, Hans Author Laudee, Pongsak text Zootaxa 2020 2020-06-19 4801 3 577 583 journal article 10.11646/zootaxa.4801.3.10 1175-5326 3904666 2F87D690-70BF-4C6E-AEBB-50820C22DBAF Hydropsyche khaonanensis n. sp. Malicky & Suwannarat Figs. 3 A–3E Type material. Holotype male ( PSUNHM ). Thailand , Tai Rom Yen National Park , Dad Fah waterfall 3, 8 o 50’N, 99 o 19’E , 911 m , 22.iv.2018 , leg. Nannaphat Suwannarat. Paratype : 1 male , Thailand , Kao Nan National Park , Klong Gray river 5, 8 o 45’N, 99 o 32’E , 1132 m , 6.iv.2018 , leg. Nannaphat Suwannarat ( PSUNHM ) . Etymology. The species is named for the type locality, Khao Nan National Park. Description. The whole insect is yellowish grey with comparatively dark eyes. Length of each forewing 8–10 mm (n = 2). Male genitalia ( Figures 3 A–3E). In dorsal view ( Fig. 3A ), segment IX forming isosceles trapezoid with Ushaped incision for one-third of its length anteriorly; posterior part of segment IX fused with segment X at shallow M-shaped line of fusion; lateral lobes of segment IX triangular and acute apically; in lateral view ( Fig. 3B ), segment IX C-shaped with anterolateral margins convex; posterior margins of segment IX setose; in ventral view ( Fig. 3C ), segment IX subrectangular with anterolateral lobes. Segment X in dorsal view ( Fig. 3A ) short with numerous of setae, posteromesal margin with 2 pointed processes; in lateral view ( Fig. 3B ), segment X somewhat triangular, beak-like posteriorly. Inferior appendages slender and long, each with basal segment slender and more than twice as long as apical segment; apical segment slender and short, apex rounded and slightly upturned in lateral view; in ventral view, inferior appendages tubular, slightly curved inward ( Fig. 3C ). Phallus axe-shaped, expanded and downcurved basally, apicodorsal end abruptly truncate and apicoventral portion curved caudad and pointed in lateral view ( Fig. 3D ). Diagnosis. The phallus of H . khaonanensis n. sp. is similar to that of H . arcturus Malicky & Chantaramongkol 2000 , but a clear difference is seen in the ventral view of the phallus ( Figs. 3E, 3F ); the two distal lateral lobes have rounded outer edges in H . khaonanensis n. sp. (3E), but in H . arcturus these lobes have short distal points which are directed outward ( Fig. 3F ).