Rhyacophila orthacantha Emoto 1979

Rhyacophila orthacantha Emoto 1979 View in CoL

( Figs 11A–11C View FIGURES 8–11 , 15A–15D View FIGURES 12–15 , 16D View FIGURE 16 )

Rhyacophila orthacantha Emoto 1979 View in CoL , 557–560, 565–568, male, female, Honshu ( Aichi); Hattori 2005, 422, 431, male, female.

Diagnosis. The male genitalia of R. orthacantha are similar to those of R. motakanta in having a short, apically bifid apicodorsal lobe of segment IX, but can be distinguished from the latter by the characters given in the diagnosis of R. motakanta . The female genitalia of this species are indistinguishable from those of R. koryne sp. nov. as indicated in the diagnosis of R. koryne sp. nov.

Specimens examined. Honshu: Tokyo: 1 male, Ôkumotori-dani, Nippara-gawa, Okutama-machi , alt. 1300 m, 5.vi.1991, T . Nozaki (TNo) . Shizuoka: 2 females, Nigori-gawa, Umegashima, Shizuoka-shi , 9.vi.2002, T . Hattori ( SPMN) ; 2 males, 1 female, Warashina-gawa, Yunoshima, Shizuoka-shi , alt. 300 m, 7.v.1995, T . Hattori ( SPMN) ; 6 males, 2 females, same locality, 11.v.2001, T . Hattori ( SPMN) ; 1 female, Ituka-zawa, Tashiro, Ikawa , Shizuoka-shi, alt. 750 m, T . Hattori ( SPMN) . Mie: 2 males, 2 females, Kawachi-dani, Yamaguchi, Fujiwara-cho, Inabe-shi , alt. 250 m, 4.vi.2006, T . Hattori ( SPMN) . Shiga: 1 male, Takatoki-gawa, Yogo-cho, Nagahama-shi , 28.v.2008, T . Ushijima (NKa) . Nara: 7 males, Kawaai, Tenkawa-mura , 26.v.1974, T . Hattori ( SPMN) ; 1 male, Dorokawa, Tenkawa-mura , 15.v.2004, H. Nishimoto ( SPMN) .

Distribution and biology. R. orthacantha is distributed in central Honshu ( Fig. 16D View FIGURE 16 : Taira et al. 2025). Adults were collected from mountain streams by sweeping or light traps in May to June. Taira (2023) reported that this species had a univoltine life cycle in central Honshu.

Japanese name. Togari-mijikao-nagare-tobikera.