Dexia fusiformis Walker, 1861

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 : 40-41

Dexia fusiformis Walker, 1861

Dexia fusiformis Walker, 1861: 266 . — Wulp 1896: 138 (catalog). — Crosskey 1976: 179 (catalog).

Diagnosis. Thorax with 2 broad longitudinal black vittae; proepisternum bare; 3 katepisternal setae; wing reddish brown to dark on basal area and along veins; legs black.

Description. Body length. 15.0− 16.2 mm.

Male. Head with dense whitish pruinosity, upper fronto-orbital plate and upper occiput with yellowish pruinosity, lunule and upper 2/3 of facial carina yellow, base of vibrissa shining black; antenna brown, apex of pedicel narrowly reddish; palpus reddish yellow, darkened on basal 2/5. Frons about 0.15 times as wide as head width; frontal vitta about 3 times as wide as fronto-orbital plate at middle; parafacial nearly parallelsided, about 3 times as wide as 1st flagellomere; facial carina long and high, apical portion rather broadly flattened on entire length, lower margin of face well produced forward; gena about 3/7 times as wide as eye height; occiput well bulged. Inner vertical seta fine, less than 1/2 eye height; outer vertical seta about 2/5 as long as inner vertical seta; ocellar seta fine hair-like, at most as long as outer vertical seta; 14−15 frontal setae, lowest seta nearly level with base of antenna; fronto-orbital plate with a row of fine hairs close to row of frontal setae; gena with several fine short hairs on anterior portion and several longer ones on posterior portion; vibrissa inserted above level of lower margin of face by about length of pedicel. Antenna falling short of lower margin of face by about 1/2 length of 1st flagellomere, 1st flagellomere about 4.5 times as long as pedicel; total width of arista including plumosity 2−3 times as wide as 1st flagellomere. Prementum slender, about 2/3 as long as eye height; palpus slightly longer than pedicel and 1st flagellomere combined.

Thorax black in ground color, supra-alar region, postalar callus and basal half of scutellum dark brown, apical half of scutellum reddish; scutum with dense yellowish white pruinosity and 2 broad longitudinal black vittae, pruinose portion between vittae about 3/5 as wide as a vitta; pleura with rather dense grayish white pruinosity. Hairs black; 2 postpronotal setae; 1 presutural and 2 postsutural acrostichal setae; 3 presutural and 3 postsutural dorsocentral setae; 2 postsutural intra-alar setae; 3 supra-alar setae, 2 katepisternal setae; proepisternum bare, katepisternum densely haired. Wing tinged with reddish brown from base to level of bifurcation of veins R 2+3 and R 4+5 between costa and stem of vein R 2+3 and R 4+5 and from base to level of base of cell bm below, tinged with brown from costa to vein R 4+5 and along veins and crossveins, the tinge fading marginally; tegula and basicosta black; lower calypter brown. Costal spine absent; relative lengths of 2nd, 3rd and 4th costal sectors approximately 6:11:4.5; vein M from dm-cu crossvein to its bend about 4.5 times distance between the bend and wing margin. Lower calypter with short fringe on outer margin. Legs black. Mid tibia with 2−3 posterodorsal setae; hind tibia with 3−5 anterodorsal, 1 posterodorsal and 1 ventral setae.

Abdomen translucent reddish yellow, black on syntergite 1+2, mid dorsal longitudinal portion of tergites 3 to 5, posterior 1/3 of tergite 3, 2/5 of tergite 4 and 1/2 of tergite 5; thin whitish pruinosity visible on side and venter of tergite 5 when seen from behind. Hairs dense, fine, short and recumbent, erect on tergite 5; syntergite 1+2 without median marginal setae, with 1 lateral marginal seta; tergite 3 without discal setae, with 2 short median marginal and 1 strong lateral marginal seta; tergite 4 with 4 irregularly set short median discal and a row of marginal setae; tergite 5 with regular rows of strong discal and marginal setae.

Female. Frons 0.31−0.32 times as wide as head width; frontal vitta about 1.5 times as wide as frontoorbital plate at middle; parafacial about 4 times as wide as 1st flagellomere at middle height; gena about 0.55 times as wide as eye height; facial carina high, broad and flattened apically. All head setae strong, ocellar seta slightly longer than prevertical seta, shorter than outer vertical seta; inner vertical seta 2.5 times as long as outer vertical seta, slightly more than 1/2 of eye height; 2 proclinate orbital setae, anterior seta slightly longer and subequal in length to inner vertical seta. Prementum longer than 3/5 of eye height. Postsutural scutum with black transverse band in front of scutellum. Wing dark on basal area and along veins; costal spine absent or very small. Abdomen black in ground color, with dense gray-white pruinosity on anterior 2/5 of tergite 3, 1/ 3−1/2 of tergite 4 and 1/2−4/5 of tergite 5; tergites 3 to 5 without discal setae. Other characters almost same as in male.

Type material examined. Holotype male of Dexia fusiformis Walker , INDONESIA, Tondano, Celebes [= Sulawesi], A.R. Wallace ( BMNH).

Additional material examined. INDONESIA. Sulawesi: 1 female, Noongan, 50 km S. of Menado , 1200 m, 2−10.xii.1973, H. Kurahashi. 1 female, Toloko, Rantepao-Palopo , Sulawesi, Sulatan , 21.ix.1979, N. Kashiwai. 1 female, 50 km W of Paso, 1000 m , Sulawesi Tengah Mountain , 2.ix.1997, H. Kurahashi. 1 female, Nokilalaki, 1500 m , Sulawesi Tengah Mt. , 3.ix.1997, H. Kurahashi ( BLKU) . Sulawesi: 1 female, Nord-Celebes, Toli , ix–xii.1895, H. Fruhstorfer ( BMNH). 1 female , Celebes. Minahasa, Tomohon , 1−9.iv.1954, A.H.G. Alston ( BMNH) .

Distribution. Indonesia (Sulawesi).

Remarks. This species is similar to D. caldwelli , but is distinguished from it in having prementum longer than 3/5 eye height, lower margin of face well produced forward, bare proepisternum, lower calypter with short fringe on outer margin, and black femora.