Hydroptila thuna Olah 1989

Hydroptila thuna Oláh, 1989

(Figs. 2, 14 A)

Hydroptila thuna Oláh, 1989, 281–282, fig. 26, male, Vietnam.

Hydroptila triangularis Wells & Dudgeon, 1990, 168–169, figs. 14–16, male, female,

Hong Kong; synonymized by Wells & Malicky (1997).

Hydroptila apiculata Yang & Xue, 1992, 26–27, male, China; Arefina, 2004, 210–211, figs 6–14, male, female, Russia (Khabarovsk, Primorye); synonymized by Malicky & Chantaramongkol (2007).

Hydroptila molione Malicky, 2004b, 293–294, fig. 3, male, Nepal; synonymized by Malicky & Chantaramongkol (2007).

Hydroptila phenianica: Shimura, 2010, 49, Japan (Yonaguni Island), misidentification.

Adult. Wings dark brown with several small lighter markings. Antennae brown to light brown with darker markings near half way and at apices.

Male. Lengths of forewing, hindwing and body 2.0– 2.4 mm, 1.6–1.9 mm and 2.1–2.5 mm, respectively (n=5). Antennae 29–30-segmented; length 1.2–1.5 mm (n=5). Ventral process of sternite VII small, apically subacute. Segment IX with large subtriangular apico-lateral apodemes. Dorsal plate semi-membranous, parallel sided for basal 3/4 and semi-circular with deep median slit in distal 1/ 4 in dorsal view. Subgenital plate shorter than dorsal plate, composed of sclerotized ventral plate and membranous dorsal lobe; ventral plate triangular in ventral view with sharply produced slender apical process and 2 fine setae at base of apical process. Phallic apparatus slender with long strap-like subapical process with short titillator. Inferior appendages almost parallel sided with apex subacute in lateral view, in ventral view narrowly triangular, directed latero-posteriad.

Female. Lengths of forewing, hindwing and body 2.4–2.9 mm, 2.0– 2.6 mm and 2.9–3.4 mm, respectively (n=5). Antennae 23-segmented; length 1.1 mm (n=2). Abdomen increasingly darker and more setose from segment I to segment VII. Sternite VI with small ventral process. Segment VIII strongly sclerotized, tergite and sternite fused laterally; tergite with middle and 2 lateral excisions on posterior margin, and 3 pairs of marginal setae; sternite with posterior margin broadly rounded; in ventral view internal triangular sclerite extended from anterior margin to segment VII. Bursa copulatrix thin, lozenge-shaped.

Specimens examined. Okinawa, Yaeyama Islands: 1 male, Yonaguni-jima, Tabaru-gawa, headwater, 11.IV.2008, N. Shimura; 4 males, 8 females, ibid., 3.III.2009, N. Shimura; 45 males, 19 females, ibid., 4.IV.2010, N. Shimura; 1 male, 1 female, Ishigaki-jima, Miyara-gawa, Kawahara-bashi, 12.IV.2005, TI, S; 1 male, Ishigakijima, Nagura-gawa, Toru-bashi, 12.III.2009, TI, L.

Remarks. This is one of the most widespread hydroptilid species in East Asia (Malicky & Chantaramongkol 2007). In Japan, it is found only in the Yaeyama Islands, the most southwestern islands, near Taiwan. It can be distinguished from H. phenianica by the features given in remarks for that species.

Distribution. Japan (Yaeyama Islands), Russian Far East (continental parts), China, Taiwan, Hong Kong, Raos, Thailand, Vietnam, Nepal, Sumatra. New to Japan.

Habitat. Adults were collected from streams in mountain and lowland areas.

Japanese name. Ajia-hime-tobikera (newly given here).