Dexia vacua
Creators: name: Zhang, Chun-Tian
name: Shima, Hiroshi
name: Chen, Xiao-Lin
Publisher: name: Zenodo
Year: 2010
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Diptera
Tachinidae
Dexia
Dexia vacua

description: Dexia vacua (Fallén, 1817)   
Figs. 85−88  
 Musca vacua Fallén, 1817: 240.   
 Dexia cincta Robineau-Desvoidy, 1830: 312. — Herting 1974: 40 (as syn. of D. vacua).   
 Dexia gracilis Robineau-Desvoidy, 1830: 313. — Robineau-Desvoidy 1863b: 389. — Herting 1974: 40 (as syn. of D. vacua).   
 Dexia aurinia Walker, 1849: 847. — Austen 1907: 343 (as syn. of D. vacua). — Crosskey 1974: 292, 305 (type material, junior syn. of D. vacua).   
 Dexia vacua: Macquart, 1835: 212. — Zetterstedt 1844: 1265, 1859: 6173. — Rondani 1862: 76. — Robineau- Desvoidy 1863b: 388. — Pandellé 1896: 160. — Bezzi & Stein 1907: 446. — Stein 1924: 238. — Lundbeck 1927: 270. — Emden 1954: 30. — Sabrosky & Arnaud 1965: 982 (catalog). — Kolomiets 1970: 61, 67 (key and redescription). — Mesnil 1980: 47 (redescription) — Herting 1984: 144 (catalog). — Richter & Farinets 1983: 816 (1st instar larva). — Chao & Liang 1992: 806 (key), misidentification. — Herting & Dely-Draskovits 1993: 366 (catalog). — Tschorsnig & Herting 1994: 81, 157. — Chao et al. 1998: 2154, misidentification. — Richter 2004: 355 (key). — Shi 2004: 90 (misidentification). — Chao et al. 2009: 576 (fauna), misidentification.   
 Diagnosis. Prementum 2.5−3 times as long as wide; 3 presutural and 3 postsutural dorsocentral setae; 2 katepisternal setae; tegula and legs reddish yellow; abdomen reddish yellow, entirely with grayish white pruinosity; syntergite 1+2 without median marginal setae.   
 Description. Mesnil (1980) redescribed this species in detail. Here we give some additional measurements and diagnostic characters.   
Body length. 7.5−9.8 mm.  
Male. Head with grayish white pruinosity. Frons about 0.14 times as wide as head width; parafacial about twice as wide as 1st flagellomere; facial carina weakly developed, low and pointed on ridge; gena about 0.4 times as wide as eye height; ocellar seta as strong as upper frontal setae; fine inner vertical seta 0.25−0.36 times as long as eye height, slightly shorter than ocellar seta; 1st flagellomere 2−3.5 times as long as pedicel; total width of arista including plumosity 2−4 times as wide as 1st flagellomere; prementum 2.5−3 times as long as wide; palpus about as long as 1st flagellomere. Thorax with 4 narrow longitudinal dark brown vittae, an inner vitta about 1/5 and outer one about 1/3 as wide as pruinose portion between inner and outer vittae on presutural scutum; scutellum reddish yellow at apex. Proepisternum bare; 1 presutural and 1−2 postsutural acrostichal setae; 3 presutural and 3 postsutural dorsocentral setae; 1−2 postsutural intra-alar setae; 2−3 supraalar setae; 2 katepisternal setae. Wing brownish, tegula reddish yellow, basicosta brown to dark; costal spine about 1.5 times as long as crossvein r-m. Lower calypter with long fringe on outer margins. Legs reddish yellow, claws and pulvilli about as long as tarsomere 5; mid tibia with 2−3 posterodorsal setae; hind tibia with 2−3 anterodorsal, 2 posterior and 2−3 ventral setae. Abdomen reddish yellow in ground color, widely black on mid-dorsal longitudinal portion, and black on posterior margin of tergites 3 to 5; dorsum entirely covered with grayish white pruinosity, sometimes broadly bare on posterior sides of tergite 3. Syntergite 1+2 with a lateral marginal seta, without median marginal setae; tergite 3 with 2 pairs of median discal, 1 pair of median marginal and 2 lateral marginal setae; tergite 4 with 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 rounded apically; apical half of cerci slender, pointed at apex; surstylus long and wide, pointed apically; postgonite distinctly shorter than basiphallus.  
 Female. Frons about 0.38 times as wide as head width; gena 0.6−0.7 times as wide as eye height; 7−8 inclinate frontal setae; 2 strong proclinate orbital setae; 1 upwardly directed prevertical seta; inner vertical seta longer than ocellar seta and as long as upper frontal setae. Thorax with gray pruinosity. Abdomen entirely covered with grayish white pruinosity; tergites 3 with 1 pair of median discal setae, tergite 4 with or without discal setae; tergite 5 without discal setae, some median setae of marginal setae shifted forward. Other characters almost same as in male.   
 Type material. Syntypes of Musca vacua Fallén, Sweden (SMNH) (not examined).   
 Material examined. FRANCE. 1 male, 1 female, St. Germain, 11−21.vii.−viii.1951, H.L. Parker, B. Herting det. (CNC). SWEDEN. 1 male, Grisslehamn, 2.viii.1925, Hedqren; 1 male, Ustharnmea, 31.vii.1935, Hedqren, Bergström det. (SMNH).   
 Distribution. ? China; Europe (northwards to Sweden); Russia (North European territory).   
 Remarks. This species has long been known from Europe and recently found in East Asia. It is similar to D. ventralis, but differs from it in having an undeveloped facial carina and almost entirely grayish white pruinosity on abdominal tergites in male. Chao et al. (1998: 2154), Shi (2004: 90) and Chao et al. (2009: 576) probably misidentified Chinese specimens of D. ventralis as D. vacua.   
 Host. Scarabaeidae: Serica brunnea L. (Tschorsnig & Herting 1994: 157).
description: Published as part of 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, pp. 1-81 in Zootaxa 2705 on pages 68-70