Exorista (Spixomyia) globosa, 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 : 1178-1180

Exorista (Spixomyia) globosa sp. nov.

( Figure 4 A–D)

Diagnosis

Eye haired. Male vertex approximately 0.21 of head width; gena approximately 0.18 of eye height; parafacial approximately twice as wide as first flagellomere; first flagellomere approximately 4.2 times as long as wide, approximately three times as long as pedicel. Male postabdomen: surstylus strongly narrowed and slightly curved dorsally on apical half in lateral view; cerci broad and strongly narrowed on apical one-third in lateral view; hypandrial arms not fused; pregonite curved ventrally at apex, without seta on dorsal portion; postgonite slender and curved ventrally at apex; epiphallus very short and narrowed; distiphallus nearly rectangular with broad membranous area on lateral surface.

Description – male

Head. Face and gena with silvery white pruinosity; fronto-orbital plate, parafacial and lower facial margin with dense golden pruinosity; frontal vitta, scape, pedicel and first flagellomere black or dark brown; palpus black on basal three-quarters, reddish yellow on apical quarter. Vertex approximately 0.21 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 mid height; gena approximately 0.18 of eye height; lower facial margin slightly produced forwards; anterior reclinate orbital seta short, subequal in length to ocellar seta, situated posterior to middle of fronto-orbital plate; eye haired; antenna with first flagellomere approximately 4.2 times as long as wide and approximately three times as long as pedicel; second aristomere as long as wide; third aristomere thickened on basal fifth.

Thorax. Dorsum and pleura black or pale brown in ground colour, with silvery white pruinosity; scutellum with apical half reddish yellow and silvery white pruinosity on basal half. 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: 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 0.6 times as long as cross-vein dm-cu.

Legs. Fore tibia with two or three anterodorsal and two posterior setae; mid tibia with two anterodorsal, two posterodorsal and one ventral seta; hind tibia with comb-like row of anterodorsal setae of rather uniform length, three or four posterodorsal and two or three ventral setae.

Abdomen. Black in ground colour; anterior third to half of third tergum and anterior half of fourth and fifth terga with dense greyish white pruinosity; posterolateral half of syntergum 1+2 to anterolateral half of fourth tergum reddish yellow. Syntergum 1+2 and third tergum without median marginal setae; third and four terga without discal setae; fourth tergum with a row of strong marginal setae; fifth tergum with rows of discal and marginal setae.

Male postabdomen. Surstylus strongly narrowed and slightly curved dorsally on apical half in lateral view; cerci broad and very narrowed on apical third in lateral view; hypandrial arms not fused; pregonite curved ventrally at apex, lacking seta; postgonite slender and curved ventrally at apex; epiphallus very short and narrowed; distiphallus nearly rectangular with broad membranous area on lateral surface.

Body length. 12.5 mm.

Female

Unknown.

Holotype

Male ( ITBC), Inobong , Crocker Range, Sabah, Malaysia, 2 May 2004, T. Tachi.

Etymology

The species is named for the ball-shaped male postabdominal characters.

Distribution

Malaysia (Sabah).

Host

Unknown.

Remarks

This species appears to be related to an Australian species, E. coras (Walker) , because of the similarities of the male postabdomen such as the pregonite, postgonite and distiphallus.

Figures

Figure 4. Male postabdomen of Exorista (Spixomyia) globosa sp. nov. (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.