Dexia extendens Walker, 1856

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 : 28-31

Dexia extendens Walker, 1856

Figs. 29−32

Dexia extendens Walker, 1856b: 126 . — Crosskey 1976: 178 (catalog). — Dear & Crosskey 1982: 116 (key). — Zhang

& Shima 2004: 53 (notes). — Zhang et al. 2004: 127 (list). — O’Hara et al. 2009: 28 (catalog). Dexia festiva Wulp, 1881: 41 . — Wulp 1896: 138 (catalog). — Crosskey 1967: 101 (as syn. of D. extendens ). Thelaira extendens: Wulp 1896: 138 (catalog). Sumatrodexia brevirostris Townsend, 1926a: 27 . — Baranov 1932: 215. — Crosskey 1967: 101 (as syn. of D.

extendens). — Crosskey 1969: 101 (type material).

Diagnosis. Thorax with 2 wide longitudinal black vittae; proepisternum hairy; 2 supra-alar setae; 2 katepisternal setae; abdominal tergites without median discal setae; surstylus blunt apically.

Description. Body length. 9.4−15.4 mm.

Male. Head with yellowish white pruinosity on fronto-orbital plate, more yellowish on parafacial and upper occiput; antenna and palpus reddish yellow. Frons 0.2−0.22 times as wide as head width; frontal vitta 1.1−1.5 times as wide as fronto-orbital plate at middle; parafacial slightly widened below, about twice as wide as 1st flagellomere at middle height; face well concave, facial carina long, sharp on ridge, lower margin weakly produced forward; gena 0.46−0.47 times as wide as eye height. Inner vertical setae 0.35−0.4 times as long as eye height, finer and shorter than frontal seta and ocellar seta; outer vertical seta fine, about 1/2 as long as inner vertical seta; ocellar seta slightly shorter than inner vertical seta; 10−12 inclinate frontal setae, lowest seta nearly level with base of antenna; fronto-orbital plate with a few fine short hairs on upper portion and several very minute hairs on lower portion, the latter invisible at low magnifications; parafacial bare; vibrissa inserted slightly above level of lower margin of face. Antenna falling short of lower margin of face by about 3 times length of pedicel, 1st flagellomere 2.5−3.0 times as long as pedicel; total width of arista including plumosity about 3 times as wide as 1st flagellomere. Prementum 3 times as long as wide, 5/11 eye height; palpus weakly clavate, slightly shorter than pedicel and 1st flagellomere combined.

Thorax black in ground color, postpronotal lobe, notopleural region and posterior portion of scutellum reddish; scutum with dense yellowish white pruinosity, 2 broad longitudinal brownish-black vittae present, supra-alar region, posterior portion of postsutural scutum and basal 1/2 of scutellum dark brown; pleura pale brown in ground color, with yellowish white pruinosity; anterodorsal corner of anepisternum to lower 1/2 of proepisternum via anterior spiracle and lower portion of proepimeron obliquely brown-black. Prosternum about twice as long as wide; hairs black; 0−1 presutural and 1−2 postsutural acrostichal setae; 3 presutural and 3 postsutural dorsocentral setae; 1 postsutural intra-alar seta; 2−3 supra-alar setae, anterior one fine or absent, proepisternum hairy; 2 katepisternal setae, katepisternum with 2−3 rows of hairs in front of mid coxa; discal scutellar seta fine. Wing hyaline, evenly tinged with pale brown; tegula black; basicosta brown to dark brown; lower calypter pale yellowish. Costal spine indistinct; relative lengths of 2nd, 3rd and 4th costal sectors approximately 2.5:4.5:2; vein M from dm-cu crossvein to its bend about 4 times distance between the bend and wing margin, appendix present or absent. Lower calypter with long fringe on outer margin. Legs reddish yellow, distal portion of femora and basal and distal portion of tibiae brown. Mid leg longest, hind tibia weakly sinuate on basal 1/4. Mid tibia with 2 posterodorsal setae; hind tibia with 1−2 anterodorsal, 1−2 posterodorsal and 1 ventral setae. Claw and pulvillus subequal in length to tarsomere 5.

Abdomen translucent reddish yellow, black on mid-dorsal longitudinal portion and posterior margin of tergites 3 and 4 and posteroventral portion of tergite 5, very thin whitish pruinosity visible on narrow anterior margin and narrow mid dorsal longitudinal portion of tergites 3 and 4 and entire tergite 5, the pruinosity with shifting appearance with direction of light on tergite 5. Syntergite 1+2 with 1 lateral marginal seta, without median marginal setae; tergite 3 without median discal setae, with 1 pair of median marginal and 1 lateral marginal setae; tergites 4 and 5 rarely with discal setae, each with a row of marginal setae. Male terminalia. Vshaped median cleft of sternite 5 deep and broad, posterior lobe narrow, slightly pointed apically, with long setae apically; cerci slender on apical half; surstylus wide and bluntly rounded at apex; basiphallus distinctly longer than postgonite; distiphallus long.

Female. Frons about 0.32 times as wide as head width; frontal vitta slightly wider than fronto-orbital plate; parafacial about 3 times as wide as 1st flagellomere at middle height; gena about 1/2 eye height; palpus about as long as prementum; head setae strong, inner vertical seta about 1/2 eye height and twice as long as outer vertical seta; ocellar seta shorter than inner vertical seta; 1 outwardly directed prevertical and 2 strong proclinate orbital setae; 9−10 inclinate frontal setae; antenna falling short of lower margin of face by about length of pedicel and 1st flagellomere combined, 1st flagellomere about 3.5 times as long as pedicel. Scutellum black on basal two-thirds and yellowish gray on distal 1/3. Wing rather pale yellowish from base to level of dm-cu crossvein and brownish toward apex, the brown tinge dense on area from bm-cu crossvein to level of dm-cu crossvein between costa and vein M and along veins M and CuA 1, fading marginally; vein M at bend with appendage. Abdomen black on most of syntergite 1+2, posterior 1/2−1/3 tergites 3 and 4 and entire tergite 5, with dense whitish pruinosity on reddish portion. Other characters as in male.

Type material examined. Lectotype female of Dexia extendens Walker (by fixation of Crosskey 1976: 178), MALAYSIA, Sarawak, Borneo ( BMNH) . Lectotype male of Dexia festiva Wulp (by fixation of

Crosskey 1976: 178), INDONESIA, Moeara Laboe, xi.1877 ( RMNH). Holotype male of Sumatrodexia brevirostris Townsend , INDONESIA, Sumatra, Fort de Kock [= Bukittinggi], 920 m, 1925, E. Jacobson ( ZMA).

Additional material examined. CHINA. 1 male, Daluo, Menghai, Xishuangbanna , Yunnan, 26.iv.1990, C.-T. Zhang ( SNU) . INDIA. Assam, Shillong , 1 male, 1 female, 6, 15.x.1920, R. Senior White, B.M. ( BMNH) . INDONESIA. 1 male, Aur Kumanis , Sumatra, iii.1915, E. Jacobson ( ZMUA) . MALAYSIA. 3 males, Muara Mongkos, 100 km NE Kuching, Borneo Sarawak, 25−27.xi.1975, H. Shima . 3 males, 30 miles N. Tapah, 300−800 m, 28.x.1975, H. Shima. 1 female, Mt. Kinabalu, Poring, 500 m, Borneo Sabah, 8.xi.1975, H. Shima . 1 female, Palawan Montible , 500 m, 28.x.1975, H. Kurahashi ( BLKU) . 1 male, Selangor, 15 miles, Lombak , 26.vii.1957, Usamru ( USNM) . 1 male, Borneo: Sarawak, Kampong, Pueh Lundu District , 690−1500 m, 25−31.v.1958, T.C. Maa . PHILIPPINES. 1 male, Palawan, 8−13 km E. of Tarumpitao Pt. 70 m, in Jungle , 21.v.1958, H.E. Milliron ( BPBM) .

Distribution. Myanmar, China (Yunnan), India, Indonesia, Malaysia ( Sarawak, Sabah, Pen. Malaysia), Philippines (Palawan).

Remarks. This species is similar to D. montana , but differs from it in having long palpus, distal portion of femora and basal and distal portions of tibiae more or less darkened, lower calypter with long fringe, and lacking discal setae on abdominal tergites.