Megaselia grandlabella, DISNEY, 2003

DISNEY, R. H. L., 2003, Tasmanian Phoridae (Diptera) and some additional Australasian species, Journal of Natural History 37 (5), pp. 505-639 : 550-552

Megaselia grandlabella sp. nov.

(figure 20)

Material

H  : male, Tasmania, Hobart, Battery Point, De Witt Street , garden, 1–11 January 1992 ( R. H. L. Disney —25-6) ( TMH).

Etymology The name refers to the enlarged labella of the male proboscis.

Diagnosis

The combination of short costa (<0.44); minute anterior pair of hairs and posterior pair of bristles on scutellum; bare mesopleuron; unforked vein 3; brown halteres; and lower supra-antennal bristles being only about half as long as upper pair and much weaker; take this species to couplet 5 on p. 92 of Borgmeier’s (1967b) keys. The closely approximated upper SAs and straight vein 4 means it runs to M. spoliata Borgmeier. However , the new species is larger (wing length> 1.5 mm, compared with <1.2 mm), the costal cilia longer (ca 0.1 mm, compared with 0.04 mm in M. spoliata ), and it lacks the well-developed hypandrial lobe of M. spoliata . The subsequently described M. biarticulata Disney runs to the same couplet, but is instantly recognized by its large, hook-shaped, left surstylus. Other diagnostic features of the new species are the short, but very wide, densely spinose labella; pale yellow palps rapidly expanding distally; no SPS vesicles in brown third antennal segment; only two bristles on notopleuron; thorax and abdominal tergites brown; hairs below basal half of brown hind femur clearly longer than those of anteroventral row of outer half; hind tibia with about a dozen posterodorsal hairs but no differentiated anterodorsals.

Male

Frons brown, wider than long and with dense but fine microsetae. Antials level with and a little closer to upper SAs than to anterolaterals, which are distinctly higher on frons. Pre-ocellars a little closer together than either is from a mediolateral, and all four bristles in an almost straight transverse row. Two or three short bristles on cheek and a long and a short bristle on jowl. Palp as figure 20B. Labrum pale brown and with greatest breadth only about two-thirds that of third antennal segment but almost 1.2× that of palp. Labella and glossa as figure 20C, the dark dorsal patches of the former being brown. Hairs of abdominal tergites small and sparse, except at rear of T 6 (figure 20A). Venter brown with a few small hairs below on segments 4 and 5; and longer and more numerous hairs, extending on to flanks, of segment 6. Hypopygium brown, the anal tube being paler, and as figure 20A. Front legs pale yellow brown, being darkest on basal third of coxa and ventral edge of femur. Basitarsus slender and all five fore-tarsal segment with posterodorsal hair palisade. Segment 5 a little longer than 4. Middle legs coloured as front pair but with dark brown coxae. Near-dorsal hair palisade extends about two-thirds of length. Hind legs generally darker than other two pairs. Wing 1.68 mm long. Costal index 0.39–0.40. Costal ratios 1.94:1. Costal cilia 0.09–0.10 mm long. The outermost of the two axillary bristles a little longer. Small hair at base of vein 3. Veins yellowish brown to brown. Membrane very lightly tinged grey.