Diplectrona albofasciata (Ulmer 1913)

(Figs 2 J–2R)

Hydromanicus albofasciatus Ulmer 1913, 49–50, male, Taiwan.

Diplectrona albofasciata: Malicky 2002, 1204, 1218, 1228, pl. 9, male, Taiwan.

Specimens examined. Iriomote-jima: 1 male, Yuchin-gawa, Yuchin-no-taki, 23.iii.2016, TI, S; 1 male, Urauchigawa, Kampire-no-taki, 85 m a.s.l., 25.iii.1999, TI & AO, S. Yonaguni-jima: 24 males, 4 females, Higawa-suigen, 31.iii.2010, N. Shimura, M; 3 males, Donan-daki, 13.iv.2011, N. Shimura (pinned).

Adult (Figs 2 J–2R). Forewings each 6.2–7.0 mm in male (n = 3), 7.1–7.6 mm long in female (n = 4). Wing venation typical in the genus. Lateral filaments of segment V as long as segment in both genders. Internal gland of segment V small, internal gland of segment VIII large in male.

Female genitalia (Figs 2 P–2R). Tergite VIII subquadrate, anterior margin wider than posterior margin in lateral aspect. Sternite VIII subquadrate with concave dorsal margin and large, nearly rectangular lateral lobes in lateral aspect. Segment IX obliquely S-shaped in lateral aspects, each antero-ventral corner slightly protruding anteriorly; receptacle of inferior appendage indistinct. Segment X oblique rectangular.

Distribution. Japan: Ryukyu (Iriomote-jima, Yonaguni-jima). Taiwan. New to Japan.

Remarks. This species was described based on the males collected from two localities (Ulmer 1913) and recorded from many localities in Taiwan (Hsu 1997; Malicky 2002). The male of this species is characterized by the long lateral filaments of segment V (same length as segment), small internal glands of segment V, large internal glands of segment VIII, and shape of genitalia (Malicky 2 0 0 2, pl. 9; Fig. 2J). The male genitalia are discriminated from those of other congeneric species mainly by segment X, i.e. each subquadrate lateral lobe with acute lateroposterior corner in dorsal aspect, and the mesocaudal lobes separated by a deep slit and their apices round in dorsal aspect (Malicky 2002; Fig. 2L). Large, pale marks of forewings are present in some Taiwanese males (Ulmer, 1913; Hsu, 1997), but absent in other Taiwanese specimens (Malicky 2002) and all Ryukyu males examined here. Malicky (personal communication 8 July 2017) suggested that they could be the same species, but further study with molecular data may be needed to clarify the taxonomic status. The female, first described here, is discriminated from that of D. burha Schmid by the concave dorsal margins of abdominal sternite VIII in lateral aspect (marked with an arrow in Fig. 2P).

Japanese name. Taiwan-miyama-shima-tobikera.