Dexia longipes (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 : 50-53

Dexia longipes (Townsend, 1926)

Figs. 61−64

Eoptilodexia longipes Townsend, 1926b: 536 . — Baranov 1932: 215.

Dexilla longipes: Crosskey 1967: 106 .

Dexia longipes: Crosskey 1976: 179 . — Dear & Crosskey 1982: 115 (key).

Diagnosis. Prementum about 6 times as long as wide; 3 katepisternal setae; legs black; thoracic pleura and venter of abdominal base with long pale hairs; syntergite 1+2 with 1 pair of median marginal setae; entire tergite 5 with rather densely grayish pruinosity.

Description. Body length. 9.8−14.5 mm.

Male. Head with dense grayish white pruinosity; frontal vitta dark brown; lunule reddish brown; antenna with 1st flagellomere reddish yellow, pedicel and arista reddish brown; palpus reddish yellow. Frons about 0.15 times as wide as head width; frontal vitta about 1.5 times as wide as fronto-orbital plate at middle; parafacial nearly parallel-sided, 2−2.5 times as wide as flagellomere; facial carina high, sharp on ridge; lower margin of face rather strongly produced forward; gena 0.40−0.44 times as wide as eye height. Inner vertical seta about 0.44 times as long as eye height, outer vertical seta fine, 3/5 as long as inner vertical setae; 11−12 frontal setae, lowest frontal seta nearly level with base of pedicel; ocellar seta strong, longer than inner vertical seta and subequal to upper frontal setae; fronto-orbital plate with only a few fine short hairs; gena with several fine hairs on lower portion; vibrissa inserted above level of lower margin of face by about 1/2 length of pedicel. Antenna falling short of lower margin of face by about 1.5 times length of pedicel; 1st flagellomere 4−5 times as long as pedicel; total width of arista including plumosity about 4 times as wide as 1st flagellomere. Prementum slender, about 6 times as long as wide or 0.7 times as long as eye height; palpus subequal in length to pedicel and 1st flagellomere combined.

Thorax black, covered with dense grayish white pruinosity; scutum with 4 longitudinal black vittae on presutural scutum and 5 on postsutural scutum, an inner vitta slightly wider than or as wide as pruinose portion between inner and outer vittae, outer vitta about twice as wide as inner one on presutural area, median vitta 1/2−1/3 as wide as inner vitta on postsutural scutum; scutellum with dark brown to brown pruinosity from base to apex. Hairs black on scutum, pleura with dense long pale hairs on katepisternum, anepimeron and meron, some black hairs mixed on upper portion; prosternum about twice as long as wide; proepisternum bare; 2 postpronotal setae; 1 presutural and 1−2 postsutural acrostichal setae; 2 presutural and 3 postsutural dorsocentral setae; 2 postsutural intra-alar setae; 2 supra-alar setae; 3 katepisternal setae; discal scutellar seta fine, slightly longer than scutellum. Wing hyaline, slightly and evenly tinged with pale brown; tegula and basicosta black. Costal spine shorter than 1/2 length of crossvein r-m; relative lengths of 2nd, 3rd and 4th costal sectors approximately 1:2.3:1.1; vein M from dm-cu crossvein to its bend about 5 times distance between the bend and wing margin, appendix short. Lower calypter pale brown, with short fringe on outer margin. Legs long, brownish black; pulvilli pale brownish. Coxae, trochanters and base of femora with pale yellowish hairs mixed with black ones; mid tibia with 3 posterodorsal setae; hind tibia with 3 anterodorsal, 2 posterodorsal and 2 ventral setae (upper one very fine). Claws and pulvilli long, fore claws and pulvilli slightly longer than tarsomere 5.

Abdomen long ovate, translucent yellow, dark brown on mid-dorsal longitudinal portion of syntergite 1+2 to tergite 4, posterior margin of tergites 3 and 4, and entire dorsum of tergite 5; very thin whitish pruinosity on anterior margin of tergites 3 and 4, and rather dense grayish pruinosity on entire tergite 5, the pruinosity on tergite 5 with tessellate appearance. Hairs rather fine long dense and black, suberect on tergite 5, pale yellowish hairs on sternite 1 and venter of syntergite 1+2; syntergite 1+2 with 1 pair of median marginal and 1 lateral marginal setae; tergite 3 with 2−3 pairs of fine median discal, 1 pair of strong median marginal, 1 strong and some weak lateral marginal setae; tergite 4 with 2−3 pairs of long median discal and a row of strong marginal setae; tergite 5 with a pair of strong median discal and a row of marginal setae. Male terminalia. Cerci slender on apical half and pointed apically; surstylus long and wide, weakly rounded at apex; postgonite about as long as basiphallus.

Female. Frons about 0.28 times as wide as head width; parafacial 2.5−3.0 times as wide as 1st flagellomere; gena about 0.47 times as wide as eye height; 5 frontal setae; 2 proclinate orbital setae; 1 prevertical seta. Fore claw and pulvillus shorter than tarsomere 5; mid and hind tibiae each with 2 anterodorsal, 3 posterior and 1 ventral setae. Abdomen ovate, with a wide longitudinal dark brown median vitta; tergites 3 and 4 each brown on posterior 1/4−1/3; tergite 5 reddish yellow, entirely covered with grayish white pruinosity. Abdominal syntergite 1+2 without median marginal setae; tergites 3 to 5 without discal setae; tergite 5 with a row of marginal setae. Other characters almost same as in male.

Type material examined. Paralectotype male of Eoptilodexia longipes Townsend (by designation of Crosskey 1976: 268), PHILIPPINES, Baguio, Benguet, Luzon, Baker ( USNM) .

Additional material examined. PHILIPPINES. 1 female, same locality as paralectotype ( USNM) . 1 male, Mountain Prov. , Abatan , Buguias, 60 km S. of Bontoc, 1800−2000 m, 1.vi.1964 . 2 males, Luzon,

Mountain Prov., Ifugao, Mayoyao , 1000−1500 m, 4−6.vii.1966. 1 male, Ifugao, Jacmal Bunhian, 24 km E. Mayayao, 800−1000 m, 10.v.1967, all by H.M. Torrevillas ( BPBM) .

Distribution. Philippines (Luzon).

Remarks. This species is similar to D. major in having the thoracic pleura and venter of abdominal base with long pale hairs, but is distinguished from it in having longer prementum, 2 pairs of longitudinal black vittae on presutural scutum, 3 katepisternal setae, black femora, and abdominal syntergite 1+2 with 1 pair of median marginal setae.