Polypedilum (Pentapedilum) vittatum Freeman

Oyewo, Emmanuel Adeoye & Saether, Ole A., 2008, Revision of Polypedilum (Pentapedilum) Kieffer and Ainuyusurika Sasa et Shirasaki (Diptera: Chironomidae), Zootaxa 1953, pp. 1-145 : 125-129

Polypedilum (Pentapedilum) vittatum Freeman

( Figs 42–43)

Polypedilum (Pentapedilum) vittatum Freeman, 1958: 300 .

Pentapedilum vittatum Freeman ; Freeman and Cranston (1980: 195).

Material examined. ZIMBABWE: Harare, holotype male, v.1956, E. T . M. Reid (B. M. 1956-317); Harare, paratypes male, v.1956, 2 females, iv.1956, E. T . M. Reid (B. M. 1956-288; 1956-317; 1956-288). UGANDA: Kasese District, Kilembe, Ruwenzori Mountains , 4500 ft. a.s.l., paratypes male, female, xii.1934 – i.1935, B. M. E. Afr. Exp., F. W. Edwards (B. M. 1935-203, 1956-203) . KENYA: Rift Valley Province, Naivasha , 2 males, G. R . C. von Someren ( BMNH) . ETHIOPIA: Addis Ababa, 1 male, x.1983, A. Harrison ( ZSM)

Diagnostic characters. The species is characterized by having numerous macrotrichia on the wing membrane, dark-banded abdominal segments, foretibial scale without spur or occasionally with minute spur, and base of superior volsella bare with 3 inner setae and projection with medially placed seta. The female genitalia is distinguished by having the dorsomesal lobe caudally narrow and ventrolateral lobe broad with brush-like bristles. The female is comparatively large with a wing length of 2.2–2.7 mm.

Male (n = 6, unless otherwise stated)

Total length 3.25–4.43, 3.82 (5) mm. Wing length 1.18–2.67, 2.13 mm. Total length / wing length 1.61– 2.19, 1.79. Wing length / length of profemur 2.11–2.39, 2.30. Thorax almost completely brown; abdominal segments with broad dark bands (Fig. 53G); femur, tibia and tarsi brown.

Head. AR 1.58–2.22, 2.01 (5). Ultimate flagellomere 746–909, 793 (5) µm. Temporal setae 13 including 3–7, 5 inner verticals; 3–5, 4 outer verticals; 2–3, 2 postorbitals. Clypeus with 20–27, 23 setae. Tentorium 155–190, 157 µm long, 5–10, 7 µm wide at posterior tentorial pit. Stipes 125–183, 155 µm long. Palpomere lengths (in µm): 26–53, 40; 42–60, 54; 165–179, 172 (5); 131–170, 151 (5); 231–316, 263 (3). Fifth palpomere / third palpomere 1.35–1.86, 1.52 (3). Third palpomere with 2–3 sensilla clavata.

Thorax ( Fig. 42B). Acrostichals 13–20, 15; dorsocentrals 10–23, 15; prealars 4–6, 5. Scutellum with 10– 13, 10 setae.

Wing ( Fig. 42A). Wing lobe moderately developed. VR 1.14–1.18, 1.16. Brachiolum with 1–3, 1 seta; R with 33–37, 35; R 1 with 27–32, 30; R 4+5 with 51–74, 63; Sc with 0–17, 8; RM with 1; M with 0–11, 5; M 1+2 with 44–63, 53; M 3+4 with 27–40, 34; Cu with 2–35, 20; Cu 1 with 14–25, 20; PCu with 4–38, 25; An with 22– 39, 31 setae. Cells r 4+5, and m 1+2, each with over 100; m 3+4 with 70–100; cell m basal of RM with 3–13, 8; an plus cu with about 70 to more than 100 macrotrichia. Squama with 11–14, 12 (5) setae.

Legs. Scale on foretibia ( Figs 42D–F) 29–57, 39 (5) µm long; rounded, without apical spur. Spurs on midtibia ( Fig. 42G) 67–76, 64 µm long; on hind tibia ( Fig. 42H) 67–76, 72 (5) µm long. Comb on midtibia 20–29, 22 (5) µm long; combs on hind tibia 24–36, 30 (5) µm and 17–24, 22 (5) µm long. Width at apex of foretibia 48–67, 53 (5) µm; of midtibia 54–60, 56 µm; of hind tibia 57–71, 62 (5) µm. Length and proportions of legs as in Table 55.

Hypopygium ( Fig. 43A). Tergite IX with 9–16, 13 (5) median setae; laterosternite IX with 2–3, 2 (5) setae. Anal point 48–74, 60 (5) µm long, 6–12, 9 (5) µm wide at base, gradually tapering to nearly parallel-sided towards 4–12, 7 (5) µm wide apex. Transverse sternapodeme 28–53, 49 (5) µm long; phallapodeme 95–121, 108 (5) µm long. Gonocoxite 123–186, 176 (5) µm long. Superior volsella ( Figs 43B–C) 74–93, 85 (5) µm long, base bare with 3–4, 3 (5) inner basal setae; projection with 1 dorsolateral seta. Inferior volsella ( Figs 43 D–E) 131–149, 140 (5) µm long, nearly parallel-sided with prominent apical seta. Gonostylus 155–193 µm long. HR 1.01–1.15, 1.08 (5); HV 1.90–2.55 (5).

Female (n = 3, unless otherwise stated)

Total length 2.85–348 (2) mm. Wing length 2.23–2.67 mm. Total length / wing length 2.15–2.68. Wing length / length of profemur 1.28–1.38 (2). Thorax brown to dark brown; abdominal segments brown without bands; femur, tibia and tarsi brown.

Head. AR 0.38–0.48. Temporal setae 9–14, including 4–5 inner verticals; 3–4 outer verticals, and 2–3 postorbitals. Clypeus with 20–34 setae. Tentorium 159–190 µm long, 5–11 µm wide at posterior tentorial pit. Stipes 140–200 µm long. Palpomere lengths (in µm): 33–55, 42–68, 131–170, 131–178, 225–363 (2).

Thorax. Acrostichals 24–34, dorsocentrals 15–23, prealars 5–6. Scutellum with 11–13 setae.

Wing. Anal lobe moderately developed. VR 1.12–1.18. Brachiolum with 1–2 setae, R with 42–43, R 1 with 39–56, R 4+5 with 74–120, Sc with 18–36, RM with 3, M with 7–17, M 1+2 with 63–74, M 3+4 with 50–59, Cu with 34–57, Cu 1 with 26–30, PCu with 48–78, and An with 38–48 setae. Cells r 4+5, m 1+2, m 3+4, cell m basal of RM, cu plus an each with more than 100 macrotrichia. Squama with 8–11 setae.

Legs. Scale on foretibia 31–50 µm long. Spurs on midtibia 69–81 µm long, on hind tibia 67–76 µm long. Comb on midtibia 21–26 µm long; combs on hind tibia 30–36 µm and 26–30 µm long. Width at apex of foretibia 55–70 µm; of midtibia 57–69 µm; of hind tibia 67–80 µm. Length and proportions of legs as in Table 56.

Genitalia ( Fig. 43F). Gonocoxite IX with 5–8 setae, tergite IX with 25–35 setae, segment X with 4–10 setae. Cercus 102–136 µm long, 5 (1) µm wide at apex, with 1 apical seta. Seminal capsule ovoid, 86–100 µm long, 44–54 µm wide, neck sclerotized, 19–24 µm long. Notum 157–214 µm long. Dorsomesal lobe ( Fig. 43I) 170–200 µm long, caudally narrow, 38–50 (2) µm wide; ventrolateral lobe ( Fig. 43H) with straight brush; apodeme lobe ( Fig. 43G) almost C-shaped. Postgenital plate triangular.

Remarks. The foretibial scale is rounded. However, one paratype from Ruwenzori Mountains, Kilembe, Uganda, bears a minute subapical spur (the foretibia of the holotype is lacking). Freeman (1958) recorded a rounded scale with a small inconspicuous spine. The abdominal segments of the female are apparently not banded; Freeman (1958) described the female abdomen as indistinctly banded. The species is very similar to P. (Pe.) sordens , differing primarily in having fewer setae on the wing membrane and the wing veins.

Distribution. Known from Zimbabwe, Uganda, Kenya and Ethiopia.