Dexia chaoi Zhang et Shima, 2010

Zhang, Chun-Tian, Shima, Hiroshi & Chen, Xiao-Lin, 2010, A review of the genus Dexia Meigen in the Palearctic and Oriental Regions (Diptera: Tachinidae) 2705, Zootaxa 2705, pp. 1-81 : 21-24

Dexia chaoi Zhang et Shima , sp. nov.

Figs. 17−20

Diagnosis. Antenna brownish black except basal 1/2−1/3 of 1st flagellomere reddish yellow; scutellum with a reverse triangular black marking on dorsal surface; abdominal syntergite 1+2 without median marginal setae.

Description. Body length. 12.6−15.0 mm.

Male. Head with antenna brownish black except basal 1/2−1/3 of 1st flagellomere reddish yellow; palpus reddish yellow, sometimes dark brown basally or mostly. Frons 1/6−1/8 head width; frontal vitta about twice as wide as fronto-orbital plate; parafacial about twice as wide as 1st flagellomere; facial carina arched in lateral view, flattened on ridge below; gena 0.4−0.5 times as wide as eye height; lower margin of face protruding forward. Inner vertical seta 0.3−0.4 times as long as eye height and slightly shorter than ocellar seta; 12 inclinate frontal setae; ocellar seta as strong as upper frontal seta; fronto-orbital plate and parafacial bare; vibrissa inserted above lower margin of face by about length of pedicel. Antenna falling short of lower margin of face by about length of 1st flagellomere, latter about 2.5 times as long as pedicel; arista long plumose, total width including plumosity 3−4 times as wide as 1st flagellomere. Prementum 3−4 times as long as wide; palpus longer than antenna, shorter than prementum.

Thorax black in ground color, with mostly brown pruinosity on scutum, grayish pruinosity on pleura, 2 pairs of longitudinal black vittae on dorsum, extending back to anterior 1/2−2/3 postsutural scutum, narrow inner vitta 1/3 as wide as pruinose portion between inner and outer vittae on presutural scutum; scutellum with a reverse triangular black marking, yellowish gray pruinosity marginally. Prosternum twice as long as wide; proepisternum bare; postpronotal lobe with 3−4 setae; 1−2 presutural and 2−3 postsutural acrostichal setae; 2 (rarely)−3 (mostly) presutural and 3 postsutural dorsocentral setae; 2 postsutural intra-alar setae; 3 supra-alar setae, anterior one about 1/2 as long as middle one; katepimeron with hairs on anterior and posterior portion, 3 katepisternal setae. Wing hyaline, brownish tinged; tegula and basicosta brownish black; calyptre yellow; halter yellow. Costal spine slightly shorter than crossvein r-m; relative lengths of 2nd, 3rd and 4th costal sectors approximately 1.2:2.2:1, short M appendix present or absent. Calypter with short fringe on outer margin. Legs long, brownish black; claws black, pulvillus yellowish. Fore tibia with 3−5 short anterodorsal setae on upper 2/3 and 2 posterior setae; mid tibia with 2−3 posterodorsal setae; hind tibia slightly sinuate, with 2−4 anterodorsal, 2 posterodorsal and 2 ventral setae.

Abdomen long ovate, yellow in ground color, with a wide black mid dorsal longitudinal vitta, with grayish white pruinosity on anterior margin of abdominal tergites 3 and 4, and almost entire tergite 5; syntergite 1+2 without brown markings on basal areas of lateral marginal setae, tergite 4 with brown posterior band, tergite 5 with an irregular brown median spot. Syntergite 1+2 without median marginal setae; tergite 3 with 2 pairs of fine median discal, rarely without them, and 1 pair of median marginal setae; tergite 4 with 2 pairs of median discal and a row of marginal setae; tergite 5 with some discal and a row of marginal setae. Male terminalia. V-shaped median cleft of sternite 5 deep, about 3/4 times as long as the sternite, posterior lobe wide and bluntly rounded at apex, with strong setae on outside and some smaller setulae on inside; distal half of cerci slender and pointed apically; surstylus slightly pointed at apex; pregonite with a protruding on upper median portion; postgonite shorter than basiphallus.

Female. Frons about 2/5 head width; gena 0.6−0.7 times as wide as eye height; 1 prevertical and 2 proclinate orbital setae, outer vertical seta about 1/2 as long as inner vertical seta. Abdomen ovate, dark brown except for apical half of tergite 5, which are mostly covered with yellowish white pruinosity, without median discal seta on tergites. Other characters almost same as in male.

Type material. Holotype male, CHINA, Lidiping, 3200−3300m, Weixi , Yunnan, 15.viii.1984, R. Wang ( IZCAS) . Paratypes CHINA. Qinghai: 1 male, Yushu, Xiaosumang , 3750−4000 m, 6.vii.1964, S.-Y. Wang ( IZCAS) . 7 males, Nangqian , 6−7.vii.1975, Q.-S. Fan, J.-S. He ( SEMC) . Shaanxi: 5 males, Ganquan, Qingquangou , 30.vii−22.viii.1971, J.-K. Yang ( CAU) . Sichuan: 1 male, Huasheng, 2800 m, Songpan , 8.viii.1993, H. Shima . 1 male, Mt. Paoma, 2600 m, Kangding , 18.viii.1993, H. Shima . 1 male, 4 females, Yajiang , 2800−3100 m, 23.viii.1993, H. Shima and X. Lin . 3 males, Zheduo Shan, 3000-3060 m, Kangding , 19−24.viii.1993, H. Shima ( BLKU) . 1 male, Markang , 2900 m, 18.viii.1983, X.-Z. Zhang . 3 males, Yidun, 3500 m, Batang , 16.viii.1982, S.-Y. Wang & H.-C. Cai ( IZCAS) . 3 males, Kangding , 7.vii.2006, C.-T. Zhang, J.-Y. Liu & L.-Y. Feng . 9 males, Gongga Shan, Yanzigou, 2000−2800 m, Luding, J.-Y. Liu, L. Chang , 17.vii.2005 . 14 males, 2 females, same locality as previous, C.-T. Zhang, J.-Y. Liu, L.-Y. Feng, 17.vii.2006 . 1 female, Kasi, 2750−3000 m, Daocheng , 12.vii.2006, L.-Y. Feng . 3 males, Daocheng, Geka to Echu Shan , 2260−4100 m, 14.vii.2006, L.-Y. Feng . 1 male, Luhuo , 16.viii.2006 ( SNU) . 2 males, 5000 ft, Chengtu , 6−16.viii.1933, D.C. Graham . 1 male, Wenchuan , 5000−9000 ft, 20−26.viii.1933, D.C. Graham ( USNM) . Xizang: 6 males, Yigong , 2300 m, 16.vi., 29-31.vii.1978, F.-S. Li . 1 male, Linzi , 3050 m, 6.vii.1978, F.-S. Li . 1 male, Tongmai , 2050 m, 27.vii.1978, F.-S. Li ( CAU) . 17 males, 1 female, Jitang, 3600 m, Chaya , 2.ix.1976, Y.-H. Han ( IZCAS) . 10 males, 3 females, Linzi , 8−11.vii.1977, J.-Y. Wu . 1 male, Milin , 2.viii.1980, J.-Y. Wu ( SEMC) . 4 males, Linzi , 3000 m, 5.viii.2003, M.-F. Wang ( SNU) . Yunnan: 2 males, 1 female, Yunshanping, Lijiang , 3200 m, 28.viii.1996, H. Shima . 1 female, Dagaoping, Baoshan , 1900−2400 m, 7−9.ix.1996, W.-X. Zhang . 1 male, Zhongdian, Tuguancun, 2500−3000 m, Deqin , 3−5.vi.1994, W.-X. Zhang ( BLKU) . 1 male, 1 female, Lidiping, 3200−3300 m, Weixi , 13−15.viii.1984, R. Wang & S.-Y. Wang ( IZCAS) . 3 males, 4 females, Geze, Shangri-la , 3200 m, 18.viii.2010, C.-T. Zhang, Q. Wang ( SNU) .

Etymology. Specific name is dedicated to the late Prof. Chien-Ming Chao for his contributions to the systematic work of Chinese Diptera .

Distribution. China (Qinghai, Shaanxi, Sichuan, Xizang, Yunnan).

Remarks. This new species is similar to D. bivittata , but differs from it in having dark apical half of 1st flagellomere, short prementum, thorax with 4 longitudinal black vittae on presutural scutum, and abdominal tergite 3 usually with 2 pairs of median discal setae.