Diplectrona aiensis Kobayashi 1987

Nozaki, Takao, 2021, The genus Diplectrona Westwood (Trichoptera: Hydropsychidae) in the Japanese main islands, Zootaxa 5082 (3), pp. 245-258 : 250-251

Diplectrona aiensis Kobayashi 1987

( Figs 3 , 7 )

Diplectrona aiensis Kobayashi 1987 , 19, 32, male; Morita 2013, 62–63; Nozaki 2016, 348, male; Tanaka 2016, 2, 5, male.

Diagnosis. Male genitalia of this species are similar to those of Diplectrona guangxiensis Sun 2017 described from China but are distinguished by the length of the lateral filaments of the abdominal segment V: Each lateral filament is about 1.7 times longer than the segment V in D. aiensis , but slightly shorter than the segment in D. guangxiensis . Furthermore, the pair of internal glands of the abdominal segment VIII of D. aiensis are larger than those of D. guangxiensis .

Adult ( Figs 3A–3J ). General appearance similar to D. kibuneana ( Fig. 3A ). On head ( Fig. 3B ), frontal setal wart (f.s.w.) small oval; each anterior setal wart (a.s.w.) divided into 3 warts, 2 anterior ones each small oval, posterior one triangular; each posterior setal wart (p.s.w.) large oval. Forewings each 7.0–9.5 mm long in male (n = 10), 9.3–11.5 mm in female (n = 10), venation similar to that of D. kibuneana ( Fig. 1C ). Pair of lateral filaments (l.f.) of abdominal segment V (V) long, each about 1.7 times as long as segment V in male ( Fig. 3C ), 1.4 times in female. Segment V with small internal gland (i.g.) in both male and female. Segment VIII (VIII) with large internal gland in male ( Fig. 3C ), slightly shorter than segment VII (VII), lacking in female.

Male genitalia ( Figs 3D–3G ). Segment IX longitudinally short in lateral aspect ( Fig. 3D ), anterior margins angled 50° in lateral aspect. Segment X (X) triangular in lateral aspect ( Fig. 3D ), with pair of mesocaudal lobes (m.c.l.) V-shaped in dorsal aspect ( Fig. 3E ); pair of lateral lobes (l.l) rectangular in dorsal aspect ( Fig. 3E ), each with apex directed dorsad and with short setae ventrally ( Fig. 3D ); preanal appendages indistinct, forming only large setose areas. Inferior appendages each with basal segment long club-like, extending beyond apex of segment X ( Fig. 3D ); distal segment slightly shorter than 1/3 of basal segment, tapering to apex, weakly curved mesad ( Fig. 3E ). Phallic apparatus thick basally and with apical 2/3 almost straight in lateral aspect (3F), thick apex with two pairs of endothecal processes dorsally, each apex somewhat sharp ( Fig. 3F ).

Female genitalia ( Figs 3H–3J ). Sternum VIII cleft from base, lateral lobes (l.l.) widely separated from each other posteriorly in ventral aspect ( Fig. 3J ). Segment IX (IX) semicircular in dorsal aspect ( Fig. 3I ), anterior margins gently convex anteriorly about 1/3 from base in lateral aspect ( Fig. 3H ); with pair of shallow slits posterodorsally; pair of short external sclerotized ribs (s.r.) ventrally ( Figs 3H, 3J ). Vulval scale (v.s.) with pair of short protrusions basolaterally in ventral aspect (marked with arrow in Fig. 3J ), apical part broadly membranous. Segment X (X) rhomboid in lateral aspect ( Fig. 3H ).

Immature stage. Morphology and biology of this species will be reported in a future work.

Specimens examined. Holotype: Male (in alcohol, M-8232), Ai (200 m), Nita-gun , Shimane, 22.vii.1985, M. Kobayashi ( KPM-NK). Honshu , Akita: 2 males, Sashimaki, Tazawa-ko, Semboku-shi, 29.vi.2012, M. Tanaka. Ibaraki: 3 males, Uwaso, Ishioka-shi, 7.vi.2008, N. Katsuma; 1 female, same locality, 15.vii. 2008, N. Katsuma; 5 males, 4 females, same locality, 4.vi.2011, N. Katsuma; 6 males, 5 female, same locality, 11.vi.2011, N. Katsuma. Aichi: 2 males, Hashigoda, Kikko, Moriyama-ku, Nagoya-shi, 16.v.2011, T. Nozaki. Mie: 1 male, Tabika, Komono-cho, alt. 85 m, 1–8.x.2000, H. Morita; 4 males, 1 female, same locality, 6.v.2006, H. Morita; 2 males, same locality, 31.v.2011, H. Morita; 3 males, 4 females, Okubano, Iga-shi, 9–22.vi.2012, H. Morita ( NK). Shiga: 1 male, Shishitobi-bashi, Seta-gawa, Oishi-higashi, Otsu-shi, 2.ix.2014, S. Kobayashi. Okayama: 1 male, Okutsu-kawanishi, Kagamino-cho, 26.vi.2013, K. Nojima ( KN). Kyushu, Saga: 1 male, Fuji-cho, Saga-shi, 6.v.2011, T. Iwai et al.

Distribution. Japan: Honshu, Kyushu.

Japanese name. Ai-shima-tobikera.

Figures

FIGURE 1. Diplectrona kibuneana Tsuda 1940. 1A–1I, male: 1A, habitus (Kochi, photographed by M. Takai), right lateral; 1B, head, dorsal; 1C, right wings, dorsal; 1D, abdominal segments V–X, left lateral; 1E, genitalia, left lateral; 1F, same, dorsal; 1G, phallic apparatus, left lateral; 1H, same, apical part, dorsal; 1I, segment X, left lateral, type series male of Hydropsyche difficultata Kobayashi. 1J–1L, female genitalia: 1J, left lateral; 1K, dorsal; 1L, ventral. Abbreviations: a.s.w. = anterior setal wart (paired), e.p. = endothecal process (paired), f.s.w. = frontal setal wart, i.a. = inferior appendage (paired), i.g. = internal gland (paired) of segment V or VIII, m.c.l. = mesocaudal lobe of segment X (paired), l.f. = lateral filament (paired), l.l. = lateral lobe of segment VIII in female or X in male (paired), p.a. = preanal appendage of segment X (paired), p.s.w. = posterior setal wart (paired), s.r. = sclerotized rib (paired), V–X = abdominal segments V–X, v.s. = vulval scale.

FIGURE 3. Diplectrona aiensis Kobayashi 1987. 3A–3G, male: 3A, habitus (Aichi), left lateral; 3B, head, dorsal; 3C, abdominal segments V–X, left lateral; 3D, genitalia, left lateral; 3E, same, dorsal; 3F, phallic apparatus, left lateral; 3G, same, apical part, dorsal. 3H–3J, female genitalia: 3H, left lateral; 3I, dorsal; 3J, ventral. Abbreviations: a.s.w. = anterior setal wart (paired), e.p. = endothecal process (paired), f.s.w. = frontal setal wart, i.a. = inferior appendage (paired), i.g. = internal gland (paired) of segment V or VIII, m.c.l. = mesocaudal lobe of segment X (paired), l.f. = lateral filament (paired), l.l. = lateral lobe of segment VIII in female or X in male (paired), p.s.w. = posterior setal wart (paired), s.r. = sclerotized rib (paired), V–X = abdominal segments V–X, v.s. = vulval scale. Arrow: see text.

FIGURE 7. Distribution of Diplectrona species on the Japanese main islands.