Polypedilum (Tripodura) falcatum Zhang, Song, Wang & Wang

Zhang, Ruilei, Song, Chao, Qi, Xin & Wang, Xinhua, 2016, Taxonomic review on the subgenus Tripodura Townes (Diptera: Chironomidae: Polypedilum) from China with eleven new species and a supplementary world checklist, Zootaxa 4136 (1), pp. 1-53 : 16-18

Polypedilum (Tripodura) falcatum Zhang, Song, Wang & Wang

Polypedilum (Tripodura) falcatum Zhang, Song, Wang & Wang, 2015: 572 .

Material examined: Holotype male (BDN. 12654), CHINA: Sichuan Province, Garzê County, Yajiang, 2830m, 14. VI. 1996, light trap, X. Wang. Paratypes: 19 males. 9 males, Sichuan Province, Baoxing County, Xilong Town, 1100m, 19. VI. 1996, light trap, X. Wang. 1 male, Sichuan Province, Daocheng County, Sang dui, 3730m, 10. VI. 1996, X. Wang. 4 males, Sichuan Province, Daocheng County, Daocheng River, 3700m, 11. VI. 1996, X. Wang. 1 male, Sichuan Province, Litang District, Shiliang River under Zhaisang Bridge, 3520m, sweep net, 13. VI. 1996, X. Wang. 2 males, Sichuan Province, Yajiang County, Xinduqiao, 3150, sweep net, 9. VI. 1996, Y, Du. 2 males, Ningxia Autonomous Region, Liuban Mountain Natural Conversation, 6. VIII. 1987, sweep net, X. Wang.

Diagnostic characters. The species can be distinguished from other allied species by the following combination of characters: presence of 2 pieces of faint marking on wing; superior volsella sickle-shaped with 0–2 outer setae; a tuft of short setae present or absent dorsally on apical inner margin of superior volsella; inferior volsella straight, uniformly tapering towards apex, bilobed apically.

Key characters of male imago. Total length 2.03–2.90, 2.52 mm. Wing length 1.35–1.88, 1.63 mm. AR 0.65– 0.80, 0.72. Temporal setae 10–12, 11. Clypeus with 12–17, 14 setae. Wing with 2 faint markings, 1 extending form basal cell m3+4 to distal cell cu1, 1 in the middle of cell an. R with 15–20, 17, R1 with 9–14, 12, R4+5 with 20–28, 24 setae. Squama with 4–5, 4 setae. Dorsocentrals 9–13, 11; acrostichals 12–17, 14; prealars 3–4, 4. Scutellum with 5– 9, 6 setae. Terminal scale of front tibia 38–50, 44 µm long, triangular and pointed apically. Front leg ratio 1.82– 2.06, 1.92.

Tergite IX sub-rectangular, with 2–3 setae placed medially on the base of anal point; anal tergite bands short, thickly bent downwards. Anal point broad, 45–65, 57 µm long; the lateral projections weak, or absent with shoulders on tergite IX; dorsally, with a V–shaped ridge bearing 5–6 short setae on each side. Superior volsella sickle-like, with 0–2 outer setae, a tuft of short setae present or absent dorsally on the apex of inner margin. Inferior volsella 75–108, 90 µm long, straight, gradually narrowed towards apex, bilobed apically; dorsally with 9–12 curved setae and a long apical seta. HR 0.88–1.03, 0.96. HV 1.76–2.22, 2.06.

Distribution. The species distributes in both the Palaearctic and Oriental China.

Remarks. The male adult of the species resembles those of P. (T.) acifer Townes and P. (T.) sidoniensis Moubayed in having sickle-like superior volsella, anal point broad and apically rounded. Wing has 2 weak markings in P. (T.) falcatum Zhang, Song, Wang & Wang , but wing marking is absent in P. (T.) acifer Townes and P. (T.) sidoniensis Moubayed. Tergite IX has 2–3 median setae in P. (T.) falcatum Zhang, Song, Wang & Wang and P. (T.) acifer , but 9 in P. (T.) sidoniensis Moubayed. The value of AR is different in above 3 species, 0.65–0.80 in P. (T.) falcatum Zhang, Song, Wang & Wang , 1.02–1.22 in P. (T.) acifer Townes , 0.4 in P. (T.) sidoniensis Moubayed.