(Figs. 7, 14 D)
Hydroptila spinosa Arefina & Armitage, 2003, 15– 16, figs. 1–2, male, female, Russian Far East (Sakhalin); Ito et al., 2010, 65, Japan (Hokkaido).
Adult. Wings dark brown with several small lighter markings. Antennae brown with no darker markings.
Male. Lengths of forewing, hindwing and body 2.6–2.8 mm, 2.3–2.5 mm and 2.5–2.6 mm, respectively (n= 5). Antennae 32–35 -segmented; length 1.3–1.5 mm (n= 5). Ventral process of sternite VII elongate, expanded in distal half, apex jagged. Segment VIII with pair of large setal patches ventrally. Segment IX with rounded antero-lateral apodemes, and lateral processes; processes directed latero-caudad, apically subacute. Dorsal plate transparent, semicircular in dorsal and ventral views, in lateral view subtriangular with subacute apex; median section membranous with several thick spines ventrally. Subgenital plate membranous, bilobed, distinctly shorter than dorsal plate. Phallic apparatus long, straight; subapical process slender, shorter than phallus and slightly curved mesad at apex. Inferior appendages strongly sclerotized, rod-shaped each with conspicuous seta subapically and several thin short setae apically; narrow in ventral view and strongly diverging.
Female. Lengths of forewing, hindwing and body 2.6 –3.0 mm, 2.0– 2.7 mm and 2.9–3.5 mm, respectively (n= 5). Antennae 25–27 -segmented; length 0.9 –1.0 mm (n= 5). Abdominal segments pale. Sternite VI with small ventral process. Segment VIII tergite and sternite indistinct, 3 pairs of long subapical setae ventrally and pair of setae dorsally; ventral sclerite dark and conspicuous, lozenge-shaped in ventral view, bearing numerous very fine spines on surface (visible under 400 magnification). Bursa copulatrix lozenge-shaped.
Specimens examined. Hokkaido: 2 males, 2 females, Shibecha-cho, Kayanuma, Shirarutoro-etoro-gawa, Tomi-bashi, 16.VII. 2009, TI, L; 222 females, Shibecha-cho, Kayanuma, Shirarutoro-etoro-gawa, 17 m, 16.VII. 2009, TI, P; 1 male, 3 females, Kushiro-shi, Akan-cho, Akan-kohan, Ibeshibetsu, 23.VII. 1996, TI & AO, L; 5 males, 7 females, ibid., 14.VII. 1997, TI & AO, L; 1 male, 5 females, ibid., 26.VII. 1999, TI & AO, L; 1 male, 2 females, ibid., 9.VIII. 2007, TI, L; 1 male, 22 females, Kushiro-shi, Akan-cho, Ibeshibetsu-gawa, 425 m, 27.VII. 1999, TI & AO, L; 1 male, 1 female, Kushiro-shi, Akan-cho, Akan-panke-to, 14.VII. 1997, TI & AO, L; 3 males, 17 females, ibid., 10.VII. 1998, TI & AO, L; 3 males, 2 females, Obihiro-shi, Kawanishi-cho, Kikankogawa, 4–21.VII. 1995, AO, M; 3 males, 37 females, Wakkanai-shi, Koitoi, Masuhoro-gawa, 20.VIII. 1997, TI & AO, L; 6 males, 28 females, ibid., 9.VIII. 1999, TI & AO, L; 3 males, 5 females, Horokanai-cho, Shumarinai, 10.VIII. 1999, TI & AO, L; 6 males, 11 females, Sapporo-shi, Kannon-zawa, 12.VII. 1998, K. Sugisima; 1 male, 8 females, Sapporo-shi, Jozankei, Otarunai-gawa, 13.VIII. 1974, TH, L; 8 males, 4 females, ibid., 26.VII. 1976, T. Kumata & M. Furukawa; 1 male, 4 females, Eniwa-shi, Izari-gawa, Honryu-nigo-bashi, 21.VIII. 2009, TI, L & P; 3 females, Eniwa-shi, Izari-gawa, Suisei-bashi, 17.VIII. 2001, TI, L; 1 female, Eniwa-shi, Izari-gawa, Eniwa-ohashi, 9–15.VII. 2005, TI, L; 1 female, Eniwa-shi, Kashiwagi-gawa, Fukajo-bashi, 25–30.VII. 2000, TI & AO, L; 1 female, ibid., 25–30.VI. 2001, TI, L; 39 males, 35 females, Eniwa-shi, Rarumanai-gawa, Hakusen-no-taki, 15– 21.VII. 2001, TI, L; 17 males, 74 females, Chitose-shi, Monbetsu-gawa, 240 m, 14.VII. 2000, TI et al., L; 2 females, Chitose-shi, Naibetsu-gawa, 18.VIII. 1990, TI, L; 1 male, 8 females, ibid., 15.VII. 2001, TI & AO, L; 3 males, 134 females, Chitose-shi, Chitose-gawa, Daiichi-usakumai-bashi, 18.VII. 2001, TI & AO, L & S; 13 males, 12 females, Erimo-cho, Utabetsu, small spring, VIII. 1990, TI, R; 2 males, Tomakomai-shi, Takaoka, headwater of Horonaigawa, 16.VI. 1981, TI, R; 1 male, Kuromatsunai-cho, Utasai-gawa, 16.VII. 2005, NK (NK); 1 female, Imakane-cho, Shimo-hakaimappu-gawa, 17.VII. 2005, NK (NK); 2 males, Imakane-cho, Pirika-skii-jo, 27.VII. 2004, TI, L; 1 male, 116 females, Shiriuchi-cho, Idesu-gawa, 8.VII. 1978, TI, L; 9 males, 22 females, Shiriuchi-cho, Idesu-gawa, Idesu-bashi, 6.VII. 1998, AO, L; 2 males, 5 females, Matsumae-cho, Oyobe-gawa, 2.VII. 2005, NK, L (NK); 5 males, 21 females, Matsumae-cho, Oyobe-gawa, Gogo-bashi, 12.IX. 2006, TI, L. Honshu. Aomori: 1 female, Mutsu-shi, Simo-ogawa, Shozu-gawa, 66 m, 17.IX. 2010, TI, L. Miyagi: 1 female, Shichigashuku-machi, Yokokawa, 500 m, 5.VII. 1998, TH, L. Fukushima: 1 female, Fukushima-shi, Iisaka-cho, Nakamoniwa, Surikamigawa, 10.X. 1997, TN. Saitama: 1 male, Chichibu-shi, Otaki-mura, Kudonosawa, 750 m, 19.V– 10.VI. 1998, T. Kagaya et al., M. Tokyo: 5 males, 31 females, Hachioji-shi, Kamiange, 28.VIII. 1991, TN. Kanagawa: 1 male, 1 female, Kiyokawa-mura, Shiomizu-gawa, 690 m, 5.VI. 1994, TH, L; 2 females, Hadano-shi, Mizunashi-zawa, Hondani, 19.VI. 1996, TN & AO; 11 males, 60 females, Yamakita-machi, Shiraishi-gawa, 26–27.IX. 1998, TN. Niigata: 1 female, Shibata-shi, Uchinokawa-gawa, 200 m, 17.VII. 1994, TH; 1 male, Minami-uonuma-shi, Yamato-machi, Mizunashi-gawa, 300 m, 18.VII. 1994, TH, L; 5 females, Asahi-mura, Miomote-gawa, Futagoshima-shinrin-koen, 10.IX. 2003, TI, L. Nagano: 1 male, Ueda-shi, Maruko-machi, Uchimura-gawa, 25.VI. 1997, K. Tojo; 3 females, Fujimi-machi, Kamanashi-gawa, 850 m, 20.IX. 1998, TH, L. Shizuoka: 2 males, 7 females, Shizuoka-shi, Kuromata, Mineyama, 300 m, 29.VIII. 1995, TH, L; 4 males, 6 females, Shizuoka-shi, Umegashima, Rokurogi, 420 m, 26.VII. 1995, TH, L; 3 females, Shizuoka-shi, Yunoshima, Warashina-gawa, 280 m, 15.X. 1995, TH, L; 9 females, ibid., 19.VIII. 1997, TH, L; 2 males, 3 females, Shizuoka-shi, Shinma, Shinmaya-gawa, 110 m, 14.VI. 2005, TH, L; 1 male, 1 female, Shizuoka-shi, Shinma, Shinmaya-gawa, 50 m, 21.V. 2009, TH, L; 5 males, 20 females, Shizuokashi, Yokosawa, short cascade, 530–550 m, 6.VI– 10.VII. 2003, TH, L; 4 females, Shizuoka-shi, Hirano, Kurobezawa, 400 m, 27.VIII. 1995, TH, L; 1 female, Shizuoka-shi, Nakahira, Abe-kawa, 250 m, 25.VII. 1998, TH, L; 3 males, Shizuoka-shi, Nyujima, 9.IX. 2008, TH, L; 3 females, Fujieda-shi, Kurata, 4.X. 2003, TH, L; 1 male, Izu-shi, Jizo-gawa, 660 m, 2.VI. 2009, TH, L; 4 males, 6 females, Mori-machi, Oguni-jinja, 5.VII– 1.VIII. 2000, K. Sugisima; 3 females, Fujieda-shi, Kurata, 4.X. 2003, TH, L. Mie: 2 males, 5 females, Kisei-cho, 30.V. 1999, H. Morita; 1 male, Kameyama-shi, Sekisuikei, 22.VII. 2000, H. Morita. Shiga: 1 male, Koka-shi, Tsuchiyama, Okawara, 10.VIII. 2008, NKA, L (MKNM). Wakayama: 4 females, Kozagawa-shi, Hirai, 12–17.VII. 1999, M. Maruyama; 1 male, Tanabe-shi, Ryujin-mura, R 371, 850 m, 28.V. 2004, TH, L. Tottori: 2 males, 5 females, Nichinan-cho, Yukawa, Wakamatsu-gawa, 580 m, 14.X. 2002, TH, L. Shikoku. Tokushima: 1 female, Tsurugi-cho, Ichiu-son, Kuwadaira, Inotani, 900 m, 25.IX. 2002, TH. Ehime: 1 male, 1 female, Kumakogen-cho, Omogo-mura, Kanmon, small stream, 23.V. 1999, TI & AO, S; 9 females, Kumakogen-cho, Omogo-mura, Teppoishi-gawa, camp site, 22.V. 1999, TI & AO, L; 6 males, 6 females, Uchiko-machi, Oda, Koyayama, 6–22.VI. 2000, E. Yamamoto & M. Doi, M; 1 female, Uchiko-machi, Odamiyama, Hondani, 31.V– 10.VI. 2001, E. Yamamoto. Kochi: 2 males, Tsunocho, Higashi-tsuno-mura, Tengu-ike, 8.V. 2004, MT, L; 1 male, 2 females, Shukunoge-shi, Isshobara, 30.IV. 2004, MT, L; 1 male, 1 female, Nangoku-shi, Nakanokawa, 14.V. 2004, MT; 1 male, 1 female, Nahari-cho, 30.VII. 1996, S. Tsukaguchi. Kyushu. Nagasaki: 1 female, Saikai-shi, Oseto, Gotsu-gawa, Iwaseto-bashi, 7.VI. 2001, T. Fujitani, L. Miyazaki: 26 males, 94 females, Nobeoka-shi, Kitagawa-cho, Kumata, Kita-gawa, 15 m, 22.IV. 2004, TH, L.
Remarks. This species is characterized by having several spines on the ventral surface of the dorsal plate in the male and a heavily sclerotized lozenge-shaped ventral sclerite in the female.
Distribution. Japan (Hokkaido, Honshu, Shikoku, Kyushu), Russian Far East (Sakhalin).
Habitat. Adults were collected mostly from streams in mountainous areas.
Japanese name. Toge-hime-tobikera.