Exorista (Spixomyia) flaviventris, Tachi, 2011

Tachi, Takuji, 2011, Three new species of Exorista Meigen (Diptera: Tachinidae), with a discussion of the evolutionary pattern of host use in the genus, Journal of Natural History 45 (19 - 20), pp. 1165-1197 : 1183-1186

Exorista (Spixomyia) flaviventris sp. nov.

( Figures 6 A–D, 8B)

Diagnosis

Male. Vertex 0.28–0.3 of head width; gena 0.29–0.32 of eye height; parafacial 1.5–2 times as wide as first flagellomere; first flagellomere 2.5–3.5 times as long as wide, and 2–2.7 times as long as pedicel; palpus black; fourth and fifth abdominal terga with yellow pruinosity contrasting with greyish yellow preceding terga. Male postabdomen: surstylus nearly straight and strongly curved dorsally at middle in lateral view; cerci somewhat narrowed on apical half, with long golden setae on apical four-fifths, apical one-sixth narrowed and curved ventrally, nearly rounded in dorsal view; hypandrial arms not fused; pregonite curved ventrally with some setae dorsally; postgonite nearly square and rounded apically; epiphallus elongate and evenly curved ventrally; distiphallus nearly rectangular with membranous area medially.

Female. Vertex approximately 0.32 of head width; gena slightly narrower, approximately 0.25 of eye height.

Description – male

Head. Face, lower part of parafacial and gena with silvery white pruinosity; frontoorbital plate and upper part of parafacial with dense golden pruinosity; frontal vitta, scape, pedicel, first flagellomere and palpus black or dark brown. Vertex 0.28–0.3 of head width; frontal vitta approximately 1.3 times as wide as fronto-orbital plate at middle; parafacial 1.5–2 times as wide as width of first flagellomere at middle height; lower facial margin not produced; gena 0.29–0.32 of eye height; anterior reclinate orbital seta situated posterior to middle of fronto-orbital plate; eye bare; antenna with first flagellomere 2.5–3.5 times as long as wide and 2–2.7 times as long as pedicel; second aristomere subequal in length to wide; third aristomere thickened on basal third.

Thorax. Dorsum and pleura black or pale brown in ground color, with silvery white pruinosity. Three presutural and four postsutural dorsocentral setae; three katepisternal setae.

Wing. Relative lengths of costal sectors second, third and fourth approximately as 4: 7: 3.8; vein M between cross-veins dm-cu and r-m approximately 2.5 times as long as that from cross-vein dm-cu to its bend; ultimate section of vein CuA 1 approximately 0.3 times as long as penultimate section and 0.67 times as long as cross-vein dm-cu.

Legs. Fore tibia with three or four anterodorsal and two posterior setae; mid tibia with three or four anterodorsal, two or three posterodorsal and one ventral setae; hind tibia with five to seven anterodorsal and three or four posterodorsal setae of unequal length and three ventral setae.

Abdomen. Black in ground colour; third tergum with dense greyish yellow pruinosity; fourth and fifth terga wholly covered with dense golden yellow pruinosity. Syntergum 1+2 and third tergum with a pair of strong and erect lateral and median marginal setae; discal setae of third and fourth terga usually lacking, but sometimes a pair of rather short setae on fourth; fourth tergum with a row of marginal setae; fifth tergum with rows of strong discal and marginal setae.

Male postabdomen. Surstylus nearly straight and strongly curved dorsally at middle in lateral view; cerci somewhat narrowed on apical half with long golden setae on apical four-fifths, apical sixth narrowed and curved ventrally, nearly rounded in dorsal view; hypandrial arms not fused; pregonite curved ventrally with some setae dorsally; postgonite nearly square and rounded apically; epiphallus elongate and evenly curved ventrally; distiphallus nearly rectangular with membranous area medially.

Body length. 10.5–12 mm.

Female

Vertex approximately 0.32 of head width; gena slightly narrower, approximately 0.25 of eye height; third and fourth abdominal terga without discal setae. Female postabdomen. Sixth sternum nearly fan-shaped in lateral view, with minute setulae; seventh sternum nearly rectangular in lateral view bearing minute setulae, with short anterior apodeme, posterior margin rather concave in ventral view.

Holotype

Male ( ITBC), Long Pa Sia , Sabah, Malaysia, 25 July 2006, H. Shima. Paratypes

Three males, 1 female ( ITBC, BLKU), same data as holotype .

Etymology

This species is named for the yellowish pruinosity on its abdominal terga.

Host

Unknown.

Remarks

This species is very similar to the Chinese species, E. penicilla Chao and Liang , but is easily distinguished from it by the yellowish pruinosity of the fourth and fifth abdominal terga.

Figures

Figure 6. Male postabdomen of Exorista (Spixomyia) flaviventris sp. nov. (A) Epandrium, cerci and surstylus in lateral view; (B) same in dorsal view (setae omitted on entire portion); (C) hypandrium, pregonite, postgonite and aedeagus in lateral view; (D) abdominal fifth sternum in dorsal view (setae omitted on left side). Scale bars 0.2 mm.