Stactobia distinguenda Botosaneanu & Nozaki, 1996 (Figs 11, 19) Stactobia distinguenda Botosaneanu & Nozaki, 1996, 60–62, holotype male, Honshu (Gifu). Diagnosis. This species belongs to the S. nielseni Species Group Schmid 1959. The male of this species is similar to that of Stactobia radovanovici Schmid 1959, described from Pakistan, in having a long sternite VIII and slender inferior appendages, but differs in the shape of the phallus: S. distinguenda has short phallic spines, S. radovanovici lacks spines. Male (Figs 11A–11E). Antennae each 18-segmented and 0.5–0.7 mm long (n = 5). Length of each forewing and hind wing 1.4–1.6 mm and 1.2–1.4 mm, respectively (n = 5). Tibial spur formula 1, 2, 4. Genitalia. Sternite VII longer than tergite VII, ventral process long with slightly expanded spiny apex. Tergite VIII longitudinally short, sternite VIII long, 4 times as long as tergite VIII, densely covered with thick setae. Tergite IX with pair of long apodemes anteriorly and pair of slender subgenital appendages at posteroventral edges, sternite IX reduced. Tergite X large, long, rectangular in lateral and dorsal views, 3 times as long as wide in lateral view, 2.5 times as long as wide in dorsal view, semimembranous, weakly sclerotized dorsally. Inferior appendages slender, directed dorsad in basal 1/7, gently curved posterad, then right and left appendages fused on meson and nearly straight in apical 3/4, almost reaching tip of tergite X. Phallus slender with apical 1/3 swollen; 2 short spines and slender bar internally; spines short, curved, situated apically and subapically, subapical one with inner hook in some specimens. Larva. Unknown. Specimens examined. HOKKAIDO. Ishikari: 2 males, Chitose-shi, Bifue-no-taki, 30.vii.2006, TI & TH. HONSHU. Shizuoka: 2 males, Shizuoka-shi, Akazawa, 19.ix.2013, TH & TI. Shiga: 1 male, Higashi-omi-shi, Eigenji, small fall near Kanzaki-gawa, 9.ix.2014, TI; 2 males, same locality, 29.v.2015, TI; 8 males, same locality, 11.vi.2016, TI. Distribution (Fig. 19). Hokkaido (Ishikari), Honshu (Gifu, Shizuoka, Shiga). New to Hokkaido. Habitat. Adults of this species were collected by TH and me near falls and hygropetric zones. Japanese name. Onaga-kaku-himetobikera (newly given here).

Published as part of Ito, Tomiko, 2017, The genus Stactobia McLachlan (Trichoptera, Hydroptilidae) in Japan, pp. 201-233 in Zootaxa 4350 (2) on page 219, DOI: 10.11646/zootaxa.4350.2.1, http://zenodo.org/record/1053028