Exorista (Spixomyia) ladelli (Baranov)

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 : 1180-1183

Exorista (Spixomyia) ladelli (Baranov)

( Figure 5 A–D) Eutachina ladelli Baranov, 1936: 108 . Holotype male ( NHM), Siam [= Thailand], Hua Hin , April 1926, leg. W.R.S. Ladell. Exorista sinica Chao, 1964: 369 . Holotype male ( IZAS), Sichuan (Emei Shan 550–750 m), 8 June 1957 .

Diagnosis

Male. Vertex approximately 0.26 of head width; gena approximately 0.2 of eye height; parafacial approximately twice as wide as first flagellomere; first flagellomere approximately 3.5 times as long as wide, approximately 2.3 times as long as pedicel. Male postabdomen: surstylus broad and slightly curved dorsally at apex in lateral view; cerci strongly excavated medially with many weak setae in lateral view, basal half rounded and apical half nearly straight in dorsal view; hypandrial arms not fused; pregonite nearly straight and strongly narrowed on apical half, without seta dorsally; postgonite slender and slightly curved ventrally at apex; epiphallus short and narrowed; distiphallus nearly rectangular with narrow membranous area medially.

Redescription –male

Head. Upper part of face and gena with silvery white pruinosity; fronto-orbital plate, parafacial and lower facial margin with golden pruinosity; frontal vitta, scape, pedicel, first flagellomere and palpus black or dark brown. Vertex approximately 0.26 of head width; frontal vitta subequal in width to fronto-orbital plate at middle; parafacial approximately twice as wide as width of first flagellomere at middle height; gena approximately 0.2 of eye height; lower facial margin slightly produced forwards; anterior reclinate orbital seta situated posterior to middle of fronto-orbital plate; eye haired; antenna with first flagellomere approximately 3.5 times as long as wide and approximately 2.3 times as long as pedicel; second aristomere approximately 2 times as long as wide; third aristomere thickened on basal two-fifths.

Thorax. Dorsum and pleura black or pale brown in ground colour, with silvery white pruinosity; apical portion of scutellum reddish orange. Three presutural and four postsutural dorsocentral setae; three katepisternal setae.

Wing. Relative lengths of costal sectors second, third and fourth approximately as 5: 6: 5; vein M between cross-veins dm-cu and r-m approximately twice as long as that from cross-vein dm-cu to its bend; ultimate section of vein CuA 1 approximately 0.27 times as long as penultimate section and approximately 0.67 times as long as cross-vein dm-cu.

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

Abdomen. Anterior third of third tergum, two-fifths of fourth tergum and half of fifth tergum with greyish white pruinosity. Syntergum 1+2 and third tergum with a pair of lateral and median marginal setae; third and four terga without discal setae; fifth tergum with some discal setae.

Male postabdomen. Surstylus broad and slightly curved dorsally at apex in lateral view; cerci strongly excavated on median portion, with many weak setae, basal half rounded and apical half nearly straight in dorsal view; hypandrial arms not fused; pregonite nearly straight and strongly narrowed on apical two-thirds, lacking seta; postgonite slender and slightly curved ventrally at apex; epiphallus short and narrowed; distiphallus nearly rectangular with narrow membranous area medially.

Body length. 12.5 mm.

Female. Unknown.

Specimens examined

One male ( BLKU), West Malaysia, 18 September 2004 .

Distribution

Malaysia; China; Thailand.

Host

Hymenopus coronatus (Olivier) (emerged from a nymph of orchid praying mantis on 28 August 2004).

Remarks

The identification of this species follows Shima (personal communication), who took notes on characters of the holotype in NHM and illustrated the male postabdomen mounted on a slide. This species was treated in subgenus Podotachina Brauer and Bergenstamm by O’Hara et al. (2009). However, the present study indicates that this species is closely related to members of the E. bisetosa group in Spixomyia . It is, therefore, transferred here to Spixomyia . A host of this species is here recorded for the first time.

Figures

Figure 5. Male postabdomen of Exorista (Spixomyia) ladelli (Baranov). (A) Epandrium, cerci and surstylus in lateral view; (B) same in dorsal view (setae omitted on left side); (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.