Dexia atripes ( Malloch, 1935 )

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 : 13-15

Dexia atripes ( Malloch, 1935)

Figs. 5−8

Calotheresia atripes Malloch, 1935 c: 592 .

Dexilla atripes: Crosskey 1967: 106 .

Dexia atripes: Crosskey 1976: 178 .

Diagnosis. Prementum 5−6 times as long as wide; inner and outer vittae on thorax merged on postsutural scutum; scutellum with grayish white pruinosity on apical 2/3; 2 presutural and 3 postsutural dorsocentral setae; femora black.

Description. Body length. 8.0− 14.1 mm.

Male. Head with dark brown frontal vitta and lunule; fronto-orbital plate, parafacial and gena with silvery white pruinosity; antenna with pedicel dark brown, 1st flagellomere reddish yellow, arista brown; prementum gleaming black, palpus reddish, darkened basally. Frons about 1/7 head width; parafacial 2−3 times as wide as 1st flagellomere; facial carina developed, high and sharp on ridge; gena about 0.38 times as wide as eye height; lower margin of face protruding forward. Inner vertical seta about 0.35 times as long as eye height; ocellar setae strong, slightly longer than frontal seta or inner vertical seta; fronto-orbital plate and parafacial bare; 8−10 inclinate frontal setae; vibrissa inserted above lower level of face. Antenna falling short of lower margin of face by about 1/2 length of 1st flagellomere, 1st flagellomere about 4 times as long as pedicel; total width of arista including plumosity about 4 times as wide as 1st flagellomere. Palpus as long as antenna, about 3/5 prementum length, latter 5.0−6.0 times as long as wide.

Thorax black in ground color, with yellow pruinosity and 4 longitudinal black vittae on dorsum, inner vitta narrow, 1/4−1/5 as wide as outer vitta and subequal in width to pruinose portion between inner and outer vittae, inner and outer vittae merged on posterior portion of presutural and postsutural scutum and appearing as 2 broad stripes; scutellum reddish yellow, basal 1/3 black, apical 2/3 with grayish white or pale yellowish white pruinosity, pleura with grayish white pruinosity except anepimeron and anterior part of katepisternum. Prosternum 2.0−2.5 times as long as wide. Proepisternum bare; 2 postsutural acrostichal setae; 2 presutural and 3 postsutural dorsocentral setae; 2 postsutural intra-alar setae; 3 supra-alar setae, anterior one hair-like, 2 postpronotal setae. Wing hyaline, yellow on base, brown to dark brown on anterior portion; tegula and basicosta black; calypter yellowish. Costal spine 1.0−1.3 times as long as crossvein r-m; vein M with an appendage on its bend, which is 0.5−1.0 times as long as crossvein r-m. Lower calypter with short fringe on outer margin. Legs black, fore tibia brownish yellow, mid and hind tibiae brown. Mid tibia with 2 posterodorsal setae, without ventral seta; hind tibia with 2−3 anterodorsal, 2−3 posterodorsal and 1 ventral setae.

Abdomen long ovate, translucent yellow in ground color, black on posterior margin of each tergites and mid dorsal longitudinal vitta, with yellowish white pruinosity on anterior 1/8 of tergite 3, 1/5−1/4 of tergite 4, and 1/3−1/2 of tergite 5. Syntergite 1+2 with 1 pair of median marginal and 1 lateral marginal setae; tergite 3 with 1 pair of median discal, 1 pair of median marginal and 1 lateral marginal setae; tergite 4 with a pair of median discal and a row of marginal setae; tergite 5 with regular rows of discal and marginal setae. Male terminalia. Posterior lobe of sternite 5 with fine setulae on inner surface, V-shapedmedian cleft deep and wide; cerci slender on apical 2/3; surstylus slightly pointed apically; pregonite short and bent; postgonite shorter than basiphallus; distiphallus long, plate-like.

Female. Frons about 0.18 times as wide as head width; frontal vitta slightly wider than fronto-orbital plate at middle; parafacial slightly narrower than 3 times width of 1st flagellomere; face well concave, facial carina rather high and long, ridge rather sharp; gena about 0.48 times as wide as eye height. Inner vertical seta about 3/5 eye height; outer vertical seta about 1/2 as long as inner seta; ocellar seta slightly shorter than inner vertical seta; 1 outwardly directed prevertical seta, subequal in length to ocellar seta; 2 proclinate orbital setae stronger than inner vertical setae; 7−8 frontal setae. 1st flagellomere about 5.4 times as long as pedicel. 3 postpronotal setae, 2 supra-alar setae, pre-alar seta absent. Wing black from base to level of costagial break, distinctly brownish on cells R 1 and R 2+3, pale brownish and hyaline on other portion; relative lengths of 2nd, 3rd and 4th costal sectors approximately 4:9:4; vein M from dm-cu crossvein to its bend about 2.3 times distance between the bend and wing margin, appendix about 1/2 length of r-m crossvein. Leg. Hind tibia with 2 anterodorsal, 2 posterodorsal and 1 ventral seta. Abdomen broadly reddish yellow, black on mid dorsal longitudinal area of syntergite 1+2 to tergite 5, posterior 1/5 of tergite 3, posterior 2/5 of tergite 4 and 1/2 of tergite 5, venter more broadly reddish yellow; scutum with rather dense yellowish white pruinosity on narrow mid dorsal and lateral margin of tergite 3, anterior 1/5−1/6 of tergite 4 and 1/2 of tergite 5, very thin whitish pruinosity visible on tergite 4 with direction of light. Syntergite 1+2 with 2 rather short median marginal; discal setae absent on tergites 3 to 5. Other characters as in male.

Type material examined. Holotype female of Calotheresia atripes Malloch, N. Borneo, Mt. Kinabalu, Kenokok 2300 ft, 25.iv.1929, MALAYSIA, H.M. Pendlebury ( BMNH) . Paratype female, 26.iv.1929, same data as holotype ( BMNH) .

Additional material examined. INDONESIA. 1 male, Noongan, 10 km S. of Menado , 1200 m, 2−10.xii.1973, H. Shima . 1 male, Mt. Sampana, Toloko Punchak –Rantepao–Palopo, Sulawesi, 19.ix.1999, N. Kashiwai ( BLKU) . 3 females, Tengah Toili , 90 km W of Luwuk, 100 m, Sulawesi, 26−30.viii.1997, H. Kurahashi (NSM, BLKU) .

Distribution. Oriental: Indonesia * (Sulawesi), Malaysia (Sabah).

Remarks. This species is similar to D. velutina and D. fulvifera , but differs from them in having a long prementum, grayish white pruinosity on scutellum, and dark brown apex of halter.