Dexia subnuda ( 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 : 62-64

Dexia subnuda ( Malloch, 1935)

Figs. 73−76

Eomyocera subnuda Malloch, 1935: 586 .

Dexilla subnuda: Crosskey 1967: 106 .

Dexia subnuda: Crosskey 1976: 179 . — Crosskey 1977: 603 (catalog).

Diagnosis. Thorax with 2 broad longitudinal black vittae; tegula black; costal spine subequal in length to r-m crossvein; abdomen with a triangular brownish black marking on each tergite in male; tergite 3 with discal setae in female.

Description. Body length. 8. 0−13.2 mm.

Male. Head with yellowish white pruinosity; antenna yellow, arista pale brown; palpus yellow. Frons about 0.16 times as wide as head width; parafacial nearly parallel-sided, about twice as wide as 1st flagellomere; face well concave, lower margin slightly produced forward, facial carina developed, rather sharply ridged on upper 1/2; gena about 0.4 times as wide as eye height. Inner vertical seta fine, about 2/5 eye height; outer vertical seta fine, about 2/3 as long as inner seta; ocellar seta strong; fronto-orbital plate almost bare; 10 inclinate frontal setae, lowest seta nearly level with base of antenna; parafacial almost bare, with several very minute hairs on upper 1/2 which are not visible at low magnification; vibrissa inserted at level of lower margin of face; gena with several rather long hairs on lower portion. Antenna falling short of lower margin of face by about 2/3 length of 1st flagellomere; 1st flagellomere about 3.8 times as long as pedicel; total width of arista including plumosity about 3 times as wide as 1st flagellomere. Prementum about 2/5 times as long as eye height; palpus slightly shorter than pedicel and 1st flagellomere combined.

Thorax black in ground color, postpronotal lobe sometimes weakly reddish; scutum with dense pale yellowish gray-white pruinosity and 2 broad longitudinal black vittae; pleura with thin grayish white pruinosity. 2 postpronotal setae; 1 presutural and 1 postsutural acrostichal setae; 3 presutural and 3 postsutural dorsocentral setae; 2 postsutural intra-alar setae; 2 supra-alar setae; 2 katepisternal setae, katepisternum with 2 rows of sparse long hairs; discal scutellar seta subequal in length to scutellum. Wing hyaline, evenly tinged with pale brown; tegula and basicosta black; lower calypter pale brown. Costal spine subequal in length to r-m crossvein; relative lengths of 2nd, 3rd and 4th costal sectors approximately 1:2:1; vein M from dm-cu crossvein about 2.5 times distance between the bend and wing margin, appendix about 2/3 as long as r-m crossvein. Lower calypter with long fringe on outer margin. Legs reddish yellow, tibiae brown; tarsi and claws black; pulvilli browish. Mid tibia with 1 posterodorsal seta; hind tibia with 2 anterodorsal, 1 posterodorsal and 1 ventral setae. Claws and pulvilli about as long as tarsomere 5.

Abdomen broadly translucent reddish yellow, brown-black on mid-dorsal longitudinal area of syntergite 1+2 to tergite 5, anterior and posterior margin of syntergite 1+2, posterior 1/5−1/6 of tergites 3 and 4 and posterior 1/2 or more of tergite 5; thin whitish pruinosity on anterior margin of tergites 3 and 4, and 1/3 of tergite 5; with 2 triangular brown-black lateral markings on each tergite. Hairs rather fine, sparse, recumbent and black, erect on tergite 5; syntergite 1+2 with 1 lateral marginal seta, without median marignal setae; tergite 3 with 2−4 median discal, 1 pair of median marginal and 1 lateral marginal setae; tergites 4 and 5 each with 2 pairs of median discal, 1 lateral discal and a row of marginal setae; median setae of marginal setae on tergite 5 slightly shifted forward; discal setae on tergites 3 and 4 sometimes irregularly set or absent. Male terminalia. Posterior lobe of sternite 5 rounded on posterior margin; cerci long and narrow, pointed apically; surstylus long and wide, and apex slightly bluntly rounded; postgonite about as long as basiphallus.

Female. Frons about 0.32 times as wide as head width; frontal vitta 2/3 as wide as fronto-orbital plate at middle; head setae strong; inner vertical seta more than 3/5 eye height; ocellar seta shorter than inner vertical seta; 1 prevertical and 2 strong proclinate orbital setae; 4 frontal setae. Antenna falling short of lower margin of face by about length of 1st flagellomere, 1st flagellomere about 5.5 times as long as pedicel. Costal spine strong, slightly longer than r-m crossvein. Claws and pulvilli slightly shorter than tarsomere 5. Abdomen sometimes more broadly blackish; abdominal tergite 3 with 2 median discal setae; tergites 4 and 5 without median discal and lateral discal setae. Other characters as in male.

Type material examined. Holotype male of Eomyocera subnuda Malloch , MALAYSIA, N. Borneo [= Sabah], Bettotan, Near Sandakan, 18.viii.1927 ( BMNH) . Paratypes. 3 males, 4 females, same locality as holotype, 13−18.viii.1927 (males), 8−21.viii.1927 (females) ( BMNH) .

Additional material examined. MALAYSIA. 1 male, N. Borneo [= Sabah], Tenompok , 1460 m, Jesselton, 30 km E., 17–21.x. 1958, L.W. Quate . 2 females, North Borneo (SK), Forest, Camp , 19 km N. of Kalabakan , 15.x.1962, 30.x.1962, K.J. Kuneherta ( BPBM) .

Distribution. Malaysia (Sabah).

Remarks. This species resembles D. divergens , but differs from it in male having 2 broad longitudinal black vittae on thoracic dorsum, brown tibiae, dark brown tergite 5, and female without discal seta on tergite 4.