(Figs 14–16)
Orthocladius nitidoscutellatus Lundström, 1915: 11.
Orthocladius (Orthocladius) trigonolabis Edwards, 1924: 170.
Orthocladius (Orthocladius) nitidoscutellatus Lundström: Saether 2004: 14; Saether 2005: 50; Makarchenko & Makarchenko 2011: 117.
Material examined. CHINA: Sichuan Province, Litang County, Shiliang River, 2 males, 13.vi.1996, light trap, X. Wang.
Diagnostic characters. The species can be separated from other members of the subgenus by having a medial projection of the gonostylus, superior volsella collar-like, inferior volsella with dorsal part short and squared and ventral part extended prominently below, and well developed crista dorsalis.
Description. Male (n = 2).
Total length 4.53–4.68 mm. Wing length 2.85–3.00 mm. Total length / wing length 1.51–1.62. Wing length / length of profemur 2.88–2.91.
Coloration. Head brown. Antenna, legs and abdomen yellowish brown. Thorax dark brown.
Head. AR 1.36–1.52. Ultimate flagellomere 750–760 µm long. Temporal setae 11–13, including 1–2 inner verticals, 4–5 outer verticals and 5–7 postorbitals. Clypeus with 12–15 setae. Cibarial pump, tentorium and stipes as in Fig. 14. Tentorium 198–240 µm long, 40–57 µm wide. Stipes 180–183 µm long, 55–63 µm wide. Palpomere lengths (in µm): 42–44, 62–79, 110–123, 110–128, 176–198. Length ratio of palpomeres 5/3 1.52–1.60.
Wing (Fig. 15). Anal lobe well developed. VR 1.06–1.09. Costal extension 30–50 µm long. R with 6 setae, other veins bare. Squama with 21–28 setae.
Thorax. Antepronotum with 4–6 setae. Dorsocentrals 8–10, acrostichals 3, prealars 4. Scutellum with 9 setae.
Legs. Spur of fore tibia 65–75 m long, spurs of mid tibia 27–29 µm and 22–26 µm long; of hind tibia 67–78 µm and 22–38 µm long. Comb of 8–11 setae, shortest seta 22–25 µm, longest seta 40–48 µm. Width at apex of fore tibia 35–48 µm, of mid tibia 45–68 µm, of hind tibia 53–66 µm. Pseudospurs present on ta 1 and ta 2 of mid and hind leg, 24–28 µm long. Lengths (in µm) and proportions of legs in Table 5.
Hypopygium (Fig. 16). Tergite IX including anal point with 20–24 setae. Laterosternite IX with 10–14 setae. Anal point 38–40 µm long, 20–23 µm wide. Phallapodeme 88–100 µm long; transverse sternapodeme 113–150 µm long, oral projections well developed. Gonocoxite 288–312 µm long, superior volsella collar-like, inferior volsella with ventral part not extended below dorsal part. Virga present, 25–30 µm long. Gonostylus widest medially, 125– 130 µm long; crista dorsalis well developed; megaseta 14–16 µm long. HR 2.30–2.40, HV 3.48–3.74.