Microchironomus deribae (Freeman)

Yan, Chuncai & Wang, Xinhua, 2006, Microchironomus Kieffer from China (Diptera: Chironomidae), Zootaxa 1108, pp. 53-68 : 56-59

Microchironomus deribae (Freeman)

( Fig. 2 A–E)

Chironomus (Cryptochironomus) deribae Freeman 1957: 395

Cryptochironomus deribae (Freeman) Tourenq 1966: 459

Leptochironomus paraderibae Laville & Tourenq 1967: 185

Leptochironomus deribae (Freeman) Ringe 1970: 315 ; Kugler 1971: 344; Pinder 1978: 126 Microchironomus deribae (Freeman) Saether 1977: 101 ; Cranston & Judd 1989: 256; Wang et al. 1991: 10; Wang 2000: 645

Material examined: CHINA: Tianjin City, Jixian County, Duliujianhe River, 1 male, 12.VI.1988, X. Wang; Gansu Province, Linze County, 1 male, 22.VI.1993, light trap, G. Liu; Neimenggu Autonomous Region, Xilinhaote City, Dongwuzhumuqinqi County, 910m a.s.l., 7 males, 7.VIII.1997, H. Li.

Male imago (n = 9, unless otherwise stated)

Total length 3.80–4.38, 4.01 mm. Wing length 1.53–2.13, 1.86 (8) mm. Total length/ wing length 1.98–2.50, 2.19 (8). Wing length/length of profemur 2.19–2.69, 2.54 (8).

Coloration: Thorax ( Fig. 2 A) dark brown, with black vittae; ventral 2/3 of preepisternum, most of anepisternum, and anterior 1/2 of postnotum black. Front legs with femora and distal 1/3 of tibia yellowish green, remaining parts of front leg dark brown, mid and hind legs yellowish green except tarsi 4 and 5 dark brown ( Fig. 2 B). Abdomen yellowish green to brown.

Head: AR 2.41–2.69, 2.53. Ultimate flagellomere 660–720, 687 µm long. Frontal tubercles rounded, 4–8, 6 (6) µm in diameter. Temporal setae 7–11, 9, including 0–1, 0 inner verticals, 2–4, 3 outer verticals, and 3–7, 5 postorbitals. Clypeus with 11–24, 15 setae. Tentorium 115–175, 137 µm long, 28–30, 29 µm wide. Palpomere lengths (in µm): 38–55, 44; 50–55, 52; 100–120, 110; 120–155, 134; 165–200, 186. Palp segment 5th/3rd 1.46–1.93, 1.70.

Thorax: Antepronotals 0–4, 2, acrostichals 0–6, 2, dorsocentrals 4–9, 6, prealars 2–4, 3. Scutellum with 1–4, 3 setae.

Wing ( Fig. 2 C): VR 1.06–1.13, 1.10 (8), R with 4–10, 7 (5) setae, R1 without setae, R4+5 with 2 setae at apex. Brachiolum with 2 or 3, 2 setae. Squama with 16–22, 18 setae.

Legs: Front tibia with 2 subapical setae, 50–90, 78 (7) and 70–75, 73 (2) µm long, spurs of middle tibia 13–20, 18 and 15–25, 20 µm long, comb with 22–32, 25 teeth, 8–10, 8 µm long; spurs of hind tibia 18–24, 20 and 22–26, 24 µm long, comb with 26–35, 31 teeth, 8–10, 10 µm long. Tarsus 1 of mid leg with sensilla chaetica 10–15, 13. Lengths (in µm) and proportions of legs as in Table 2 .

Hypopygium ( Fig. 2 D–E): Tergite IX with 0–5, 2 setae. Laterosternite IX with 2–5, 4 setae. Anal point flake–shape, rounded apically, 60–98, 82 µm long, 25–33, 29 µm wide at base, 18–25, 21 µm wide at apex, with V­shaped ridge bearing 12– 18, 16 setae and numerous microtrichia. Ninth tergite with 2 lobes near base of anal point, with 3–4, 3 (8) setae and covered with microtrichia. Superior volsella 35–75, 47 µm long with 3 or 4, 3 setae and without microtrichia. Anal tergite bands V shaped, not united in middle. Phallapodeme 55–133, 91 µm long. Transverse sternapodeme 30–88, 54 µm long. Gonocoxite 100–138, 117 µm long, with 3–5, 4 strong setae along inner margin. Gonostylus 188–225, 210 µm long, strongly incurved and with swollen basally, and with tooth apically, bearing 18–28, 23 setae along inner margin. HR 0.44–0.73, 0.56, HV 1.69–2.12, 1.92.

Distribution: The species is distributed in the Palaearctic, Afrotropical and Oriental Regions, and occurs in both Palaearctic and Oriental China.

Remarks: Specimens of this species were misidentified and wrongly recorded from China as Cryptochironomus chlorostolus (Kieffer) by Wang et al. (1977).

Figures

FIGURE 2. Microchironomus deribae (Freeman), Chinese specimen. A, thorax. B, legs; a, front leg; b, mid leg; c, hind leg. C, wing. D, dorsal view of hypopygium. E, ventral view of hypopygium.

Tables

TABLE 2. Lengths (µm) and proportion of legs of Microchironomus deribae (Freeman), male (n = 9).

	fe	ti	ta1	ta2	ta3	ta4	ta5	LR
p1	700–780, 732	520–610, 563	730–820, 767	450–510, 478	380–410, 386	250–270, 258	90–150, 134	1.30–1.44, 1.36
p2	710–780, 737	670–760, 711	330–370, 339	200–230, 214	160–180, 171	100–130, 116	100–110, 103	0.45–0.49, 0.48
p3	800–860, 819	820–920, 862	530–600, 553	320–350, 328	280–300, 288	160–170, 165	120–130, 123	0.61–0.67, 0.65