Cydistomyia torresi (Ferguson & Hill)

Mackerras, I. M., Spratt, D. M. & Yeates, D. K., 2008, Revision of the horse fly genera Lissimas and Cydistomyia (Diptera: Tabanidae: Diachlorini) of Australia, Zootaxa 1886 (1), pp. 1-80 : 19-20

Cydistomyia torresi (Ferguson & Hill)

( Fig. 15 )

* Tabanus torresi Ferguson & Hill, 1922: 257 ; Hardy 1939: 42, 1944: 83. Holoype female, Qld, Moa Island (syn. Banks Island), Torres Strait, Feb. 1921, McLennan (ANIC).

Cydistomyia torresi ; Mackerras 1959: 166, 1964: 146, figs 103, 112, 115; Daniels, 1989: 288; Bickel & Elliot, 1998 - 2005: 4.

Cydistomyia nigerrima Oldroyd, 1949: 351 , fig. 70; Mackerras 1964: 146 (syn. of torresi Ferguson & Hill ). Type female,

New Guinea, Milne Bay, Feb. 1943, Mackerras (Not in ANIC, presumed lost) .

Australian material examined. 6 ♀.

Diagnosis. This small species, length 11–13 mm, belongs to the Papuan C. albithorax group. Together with C. danielsorum , C. palmensis and C. pseudoardens , it represents a recent intrusion from New Guinea. Distinguished from C. danielsorum by the much longer extension on the callus, reaching upper and middle third of frons; palps black rather than fawn grey; absence of grey vitta with white triangles on abdominal tergites and venter black rather than pale grey. It is close to C. palmensis and similar in size, but distinguished by darker colouration of frons, antennae and legs, black palpi, quadrate shape of callus, long antennal scape, more conspicuous pale fringe around posterior half of thorax, and more conspicuous pale apical bands and lateral triangles on abdominal tergites.

Female. Head. Eyes (relaxed) dark brown with hint of green, bare. Frons brown, of variable but narrow width, index 5.0–5.8, tomentum at eye margins yellowish fawn, some golden hairs among dark ones above; vertex not hollow; vertical triangle ill-defined; ocellar tubercle not observed; callus deep brown, quadrate, with abrupt narrow blackish extension to junction of upper and middle third of frons, almost full width of frons at its base. Subcallus and top of parafacials brown, remainder of parafacials and face creamy white, with white hairs; beard creamy white. Antennae dark brown, scape and pedicel with dense black hairs, basal plate reddish orange, style almost black; antennal shape similar to palmensis except that scape is almost twice as long as wide. Palpi characteristically black, slightly shiny, with short black hairs.

Thorax. Scutum and scutellum brown, with dense fawn-yellow tomentum giving paler appearance to lateral margins, paler margins better defined than in palmensis , hairs mixed black and appressed cream to yellowish; scutellum much paler than in palmensis , pale hairs from wing root backwards and on scutellum relatively dense, greyish white, forming conspicuous fringe around posterior half of thorax. Pleura somewhat darker, creamy yellow above, greyish below.

Legs. Fore tibiae with basal third black, rather shiny; mid and hind tibiae mostly dark brown, hairs entirely black, except for some creamy ones below on hind femora.

Wings. Greyish to almost clear; costal cell conspicuously brownish yellow; sc and R 1 blackish, stigma bright brown, remaining veins dark brown, R 4 strongly angulate and may have vestige of appendix on one or both wings.

Abdomen. Tergites 1 and 2 brown, remainder blackish brown; tergites 2–6 with well-defined fawn-cream apical bands and small lateral triangles bearing creamy hairs; on 2 nd tergite only a vague median triangle or vitta, remaining hairs on dorsum black. Venter black, with black hairs; sternites 2–6 with fairly uniform creamy fawn apical bands, bearing creamy white hairs, 7 th sternite entirely dark.

Distribution. Known in Australia only from Torres Strait Islands QLD. QLD: Torres Strait, Moa Is., Nov., Feb., McLennan; Badu, biting, Apr., E.N. Marks; Horn Is., Dec., Houston and Sadler.

Figures

FIGURES 13–15. 13. Cydistomyia casuarinae (English, Mackerras & Dyce) frons, palp, antenna, female terminalia, sternite 8. 14. Cydistomyia cyanea (Wiedemann) frons, palp, antenna, female terminalia, sternite 8, spermathecal bulb. 15. Cydistomyia torresi (Ferguson & Hill) frons, palp, antenna, female terminalia, sternite 8.