Dexia sumatrensis (Townsend, 1926)

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 : 64-66

Dexia sumatrensis (Townsend, 1926) , status nov.

Figs. 77−80

Eomyoceropsis sumatrensis Townsend, 1926a: 29 . — Crosskey 1969: 94 (type material). — Crosskey 1976: 179 (as syn. of D. fulvifera , misidentification). — Crosskey 1977: 602 (catalog, as syn of D. fulvifera ).

Dexilla sumatrensis: Crosskey 1967: 106 .

Diagnosis. Frons 0.17−0.22 times as wide as head width; prementum 7−8 times as long as wide; thoracic dorsum with 4 longitudinal vittae; 2 katepisternal setae; costal spine short, at most 1/2 as long as crossvein r– m; lower calypter with short fringe; legs black.

Description. Body length. Male: 14.0− 17.5 mm, female: 12.3−13.7 mm.

Male. Head with dense yellowish white pruinosity; lunule brown; antenna reddish yellow, pedicel reddish brown, arista brown; palpus reddish yellow, darkened basally. Frons 0.17−0.22 times as wide as head width; frontal vitta slightly less than twice width of fronto-orbital plate at middle; parafacial nearly parallel-sided, 3−4 times as wide as 1st flagellomere; gena 0.46−0.49 times as wide as eye height; facial carina developed, ridge high and flattened; lower margin of face protruded forward. Inner vertical seta 0.3−0.4 times as long as eye height or as long as ocellar seta; outer vertical seta fine, 1/2−3/4 as long as inner seta; fronto-orbital plate with some fine short hairs inside; 11−12 inclinate frontal setae, lowest seta nearly level with upper edge of lunule; gena with several fine short hairs on anterior and lower portions; vibrissa inserted above level of lower margin of face. Antenna falling short of lower margin of face by about 2/3 length of 1st flagellomere, latter 4−5 times as long as pedicel; pedicel with a long seta about 2.5 times as long as pedicel; total width of arista including plumosity about 4 times as wide as 1st flagellomere. Prementum 7−8 times as long as wide; palpus longer than antenna.

Thorax black in ground color, with yellowish gray pruinosity; scutum with 4 longitudinal dark vittae on presutural area, an inner vitta 0.5−0.6 as wide as pruinose portion between inner and outer vittae on presutural scutum; scutellum reddish brown apically. All thoracic hairs black; 3 postpronotal setae nearly in a straight line, anterior one weak; 0−1 presutural and 1−2 postsutural acrostichal setae; 2 presutural and 3 postsutural dorsocentral setae; 2 postsutural intra-alar setae; 3 supra-alar setae, anterior one shifted outwards, about 2/5 as long as second; 2 katepisternal setae, katepisternum with 3−4 rows of rather dense fine hairs. Wing distinctly brownish on anterior portion along veins; basicosta and tegula black; lower calypter pale yellowish. Costal spine fine, at most 1/2 as long as r-m crossvein; relative lengths of 2nd, 3rd and 4th costal sectors approximately 3:8:3; vein M from dm-cu crossvein to its bend about 3.5 times distance between the bend and wing margin, appendix rather short. Lower calypter with short fringe on outer margin. Legs black; pulvilli pale brownish. Mid tibia with 2 posterodorsal setae; hind tibia with 5−6 anterodorsal, 2−3 posterodorsal and 2 ventral setae; fore claws and pulvilli longer than tarsomere 5.

Abdomen translucent yellow, black on mid dorsal longitudinal portion, posterior 1/8−1/4 of tergite 3, 1/ 3−1/5 of tergite 4 and 1/2 of tergite 5; thin whitish pruinosity on anterior margin of tergites 3 and 4 and entire tergite 5. Abdominal syntergite 1+2 with 2 median marginal and 1 lateral marginal setae; tergite 3 with 2 median discal, 2 median marginal and 1−2 lateral marginal setae; tergite 4 with 1−2 pairs of median discal and a row of marginal setae; tergite 5 with some discal and a row of marginal setae. Male terminalia. Posteror lobe of sternite 5 about 2/3 length of the sternite and blunt apically, with some long setae; apical half of cerci slender, pointed at apex; surstylus narrow, slightly pointed apically; postgonite about as long as basiphallus.

Female. Frons about 1/3 as wide as head width, widened anteriorly; outer vertical seta distinct; 5−7 frontal setae; 2 proclinate orbital setae; claws and pulvilli shorter than tarsomere 5; abdomen wide ovate, without discal setae on tergites. Other characters almost as in male.

Type material examined. Holotype male of Eumyoceropsis sumatrensis Townsend , INDONESIA, Fort de Kock [= Bukittinggi], Sumatra, x.1913, E. Jacobson ( ZMUA).

Additional material examined. INDONESIA. 5 males, 3 females, 50 km S. of Menado , 1200 m, Noongan, Sulawesi, 2−10.xii.1973, H. Kurahashi ( BLKU) .

Distribution. Indonesia (Sulawesi, Sumatra).

Remarks. This species was regarded as a junior synonym of D. fulvifera Röder by Crosskey (1976), but is here treated as a distinct species. It is similar to D. fulvifera , but differs from it in wider frons, longer prementum, shorter costal spine, and no black band on posterior margin of postsutural scutum.