Cydistomyia triangularis Mackerras & Spratt, 2008

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 : 44-45

Cydistomyia triangularis Mackerras & Spratt , sp. nov.

( Fig. 32 )

Type material. Holotype female, Qld, nr Teewah Creek , Cooloola National Park ,, Apr., J. & A. Skevington ( QM # T144396 ) . Paratype females (6), same data as for holotype ( QM) .

Diagnosis. A medium sized 10–12 mm dark brown species with black median abdominal vitta, to be distinguished from C. duplonotata and C. improcerus by generally smaller size, absence of narrower median vitta or triangles of pale hairs on black median vitta, and large shiny dark brown, bulging callus shaped like an isosceles triangle, practically full width of frons at its base and with anterior extension to ocellar tubercle. Further distinguished from C. duplonotata by dark brown to black undersized antennae with stubby basal plate with small dorsal right angle and gentle ventral angle opposite. Further distinguished from C. improcerus by presence of gently rounded ventral angle on basal plate and much darker palps and legs.

Female. Head. Eyes (relaxed) green, without hairs. Frons divergent, index 4.2, tomentum grey, with few short black hairs; vertex flat, vertical triangle greyish black with black hairs; ocellar tubercle bulging, shiny dark brown, anterior ocellus usually present. Callus shiny dark brown, bulging, triangular, almost full width of frons at base and lower lateral margins, extending to ocellar tubercle. Subcallus with grey brown tomentum, no hairs; parafacials and face grey, with black hairs; beard long mixed black and white hairs. Short, undersized antennal flagellum; scape and pedicel grey brown with black hairs; pedicel with short anterior prolongation; basal plate as wide as long, stubby, dark brown, with small dorsal right angle and gently rounded ventral angle opposite; Style black. Palpi grey-brown with dense black hairs.

Thorax. Scutum and scutellum dark grey with scattered short mixed black and white hairs. Pleura grey with black and white hairs.

Legs. Fore femora black with black hairs, remainder of legs dark brown with black hairs.

Wings. Brown, with brown suffusion in costal cell and along all veins, stigma brown.

Abdomen. Brown with black median vitta, short black hairs, no bands or median triangles on tergites. With patch of white hairs laterally on most tergites. Venter lighter brown, with black hairs, with narrow apical bands with fine white hairs on margins of sternites 2–6.

Distribution. Known only from type locality near Cooloola, QLD.

Etymology. The specific epithet derives from the Latin for triangular and refers to the very large triangular callus of the species.

Figures

FIGURES 31–33. 31. Cydistomyia pilosus Mackerras & Spratt, sp. nov. frons, palp, antenna, female terminalia, sternite 8, spermathecal bulb. 32. Cydistomyia triangularis Mackerras & Spratt, sp. nov. frons, palp, antenna, female terminalia, sternite 8, spermathecal bulb. 33. Cydistomyia duplonotata (Ricardo) frons, palp, antenna, female terminalia, sternite 8, spermathecal bulb.