Megaselia trudiae, DISNEY, 2003

DISNEY, R. H. L., 2003, Tasmanian Phoridae (Diptera) and some additional Australasian species, Journal of Natural History 37 (5), pp. 505-639 : 590-592

Megaselia trudiae sp. nov.

(figure 45B)

Material

H  : male, Tasmania, Mount Field National Park, Russell Falls , 11 January 1992 ( R. H. L. Disney —25-9) ( TMH).

Etymology The species is named after my daughter, Trudia Climie.

Diagnosis

The combination of scutellum with anterior pair of small hairs (shorter and finer than those at rear of scutum) and posterior pair of bristles; mesopleuron with 13 short hairs; and costal index 0.43; will take this species to group V of Borgmeier’s (1967a) keys, to M. turbidipennis Bormeier. However , the near-dorsal hair palisade of the mid tibia extends only about two-thirds of length in this species, but to nearly three-quarters in M. trudiae , and its costal cilia are <0.1 mm long, but 0.13–0.14 mm in M. trudiae . If some specimens turn up with a costal index>0.43 then they would run to group IV. The combination of a lack of differentiated anterodorsal hairs on hind tibia; yellow haltere knob; forked vein 3; four supra-antennal bristles; long costal cilia; and costal ratios of 3.6–3.7:1.6:1; will take this species to couplet 10 (p. 206), to M. agnatoides Beyer. However , the costal cilia of the latter are longer (0.2 mm) and its costal index is 0.5. Labella not enlarged and with few spinules below; both left and right lobes of hypandrium vestigial.

Male

Frons brown, broader than long, with numerous fine microsetae, and with 68–80 hairs. Lower SA bristles robust, but only about 0.8× as long as upper SAs. Antials clearly closer to anterolaterals than to upper SAs, but slightly lower on frons; the ALs and upper SAs being about level. Bristles of middle row in an almost straight transverse row but pre-ocellars further apart than either is from a mediolateral. Six bristles on cheek and jowl forming a single series which are progressively stronger. Third antennal segment brown and without SPS vesicles. Palps paler yellowish brown, with six bristles (the three most apical being long) and as many almost bristle-like hairs. The yellowish brown labrum with greatest width only about 0.7× that of third antennal segment. Labium pale yellow lightly tinged brown. Thorax brown, with three bristles on notopleuron. Abdominal tergites brown with short hairs, except at rear of T 6. Venter greyish brown, with small hairs below segments 3–6. Hypopygium brown and as figure 45B. Legs brown, but front tibia and tarsus more yellowish. Front tibia with an anterodorsal row of spinules in lower twothirds. Basitarsus slender and posterodorsal hair palisades only present on segments 1–4. Hairs below basal half of hind femur not strong, but some are clearly longer than those of anteroventral row of outer half. About 14 differentiated posterodorsal hairs on hind tibia, but those in upper third are fine. Wings 1.5–1.6 mm long. Vein Sc not reaching R. One or two fine hairs at base of vein 3. Axillary ridge with

1

three bristles, the outer two being subequal to costal cilia. Veins yellowish brown. Membrane lightly tinged yellowish grey.