Diamesa serratosioi Willassen (Makarchenko 1985

Diamesa serratosioi Willassen

(Figs. 19–22)

Diamesa serratosioi Willassen, 1986: 116; Ashe & O’Connor 2009: 284; Makarchenko et al. 2022: 80.

Material examined. NORWAY: Paratype adult male, Z. M. Bergen Type N 41, slide NE 61; Ekse, Hoi, Vaksdal, 24–30. VI.1976, leg. T. Andersen. RUSSIA: 3 adult males, Republic of Khakassia, Tashtypsky District, unnamed stream in the basin of the Bolshoy On River, ultraviolet lamp, 51°42’58.2”N 89°51’25.8”E, altitude 1953 m a.s.l., 8–9.VIII.2020, leg. V. Dragan; 2 adult males, Chukotka Autonomous Okrug, Anadyrskyi District, unnamed stream of Velikaya River basin, 1.VIII.1980, leg. E. Makarchenko; 2 adult males, the same data except Chukotsky District, Chegitun River, 23.VII.1981, leg. E. Makarchenko; 2 adult males, Khabarovsk Territory, Solnechnyi District, Gornyi Village, Silinka River (Amur River basin), 26.VII.1983, leg. E. Makarchenko; 6 adult males, Kamchatka, unnamed stream, about 30 km from Esso Village, light trap, 9.VII.1996, leg. E. Makarchenko; 2 adult males, Magadan Region, Olskyi District, 137 km of Kolymskaya Road, Ola River, 1. V.2016, 60.412194 N, 151.514564 E, leg. Е. Khamenkova.

Description

Adult male (n = 6, except when otherwise stated). Total length 2.3–3.0 mm. Total length/wing length 0.82– 1.0.

Coloration. Dark brown to brown. Legs brown, sometimes basal 1/3 of femur brownish-yellow. Wings grayish to gray, venation brownish.

Head. Eyes hairy, reniform. Temporal setae including 3–4 frontals, 5–6 verticals. Clypeus with 2–7 setae. Antenna with 8 flagellomeres and reduced plume of setae; terminal flagellomere with 2 subapical setae, 24–32 μm long. Length of 1–8 flagellomeres (μm): 68–104, 36–48, 36–40, 28–32, 28–32, 24–28, 28–36, 68–116; AR 0.25–0.42. Palpomere length (μm): 28–48, 40–48, 76–116, 64–100, 108–156. Palpomere 3 in distal part with sensilla capitata with diameter 12–16 μm. Head width/palpal length 1.05–1.22. Antennal length/palpal length 0.90–1.08.

Thorax. Antepronotum with 6–12 ventrolateral setae. Dorsocentrals 7–12, prealars 3–5, scutellars 22–35.

Wing. Length 2.44–3.0 mm, width 0.72–1.1 mm. Anal lobe rounded angular. Squama with 15–25 setae. R and R 1 with 17–22 setae, R 4+5 with 4–7 setae. RM/MCu 2.3–2.5.

Legs. Spur of front tibia 24–36 µm long. Spurs of mid tibia 36–44 µm and 32–48 µm long. Spurs of hind tibia 64–84 µm and 32–44 µm long. Hind tibial comb with 16–18 setae. Length (μm) and proportions of leg segments as in Table 7.

Hypopygium (Figs. 19–22). Laterosternite IX extending beyond posterior margin of tergite IX by 56–80 µm, with weak 18–20 setae, 40–52 µm long (Figs. 20, 22). Tergite IX with 16–18 setae, 20–32 µm long and with pale hyaline anal point, 26–28 µm long, which is not visible from above, in lateral view pointing down (Fig. 21); posterior margin of tergite IX rounded; tergite bands Y-type (Figs. 20, 22). Transverse sternapodeme (TSA) triangular, peaked, 88–140 µm high, 160–196 µm wide at the base; TSA height/TSA width 0.52–0.83. Gonocoxite 312–400 µm long, superior volsella covered with microtrichia and sometimes short setae (Fig. 19). Gonostylus 172–204 µm long, broad at base, more or less strongly curved, with megaseta which in form of wide terminal spine, 4–5 µm long, 3–5 apical teeth and 2 subterminal setae. HR 1.76–2.15.

Pupa and larva unknown.

Remarks. D. serratosioi from Norway and Sweden was previously described as D. davisi Edwards by SerraTosio (1971). We recoded this species from Russia for Khakassia Republic (Makarchenko et al. 2022). This is the first information about the location of D. serratosioi in the Russian Far East.

Distribution. Known from Finland, Norway, Sweden (Ashe & O’Connor 2009), Khakassia and Russian Far East (Chukotka and Magadan Region, Amur River basin of Khabarovsk Territory).