Megaselia tetrabrevis, DISNEY, 2003

DISNEY, R. H. L., 2003, Tasmanian Phoridae (Diptera) and some additional Australasian species, Journal of Natural History 37 (5), pp. 505-639 : 586-588

Megaselia tetrabrevis sp. nov.

(figure 43)

Material

H  : male, Tasmania, Battery Point, De Witt Street , garden, 10–12 June 1995 ( R. H. L. Disney —25-21) ( TMH).

Etymology The name refers to the shortened fourth tarsal segments on the middle legs.

Diagnosis

The combination of scutellum with anterior pair of minute hairs and posterior pair of bristles; bare mesopleuron; costal index 0.52; forked vein 3; no differentiated anterodorsal hairs on hind tibia; fine, but dense, microsetae on frons; relatively short hairs on abdominal tergites; segment 4 of mid tarsus clearly shorter than 5; and costal section 1 longer than 2; takes this species to couplet 46 on p. 88 of Borgmeier’s (1967b) keys. The uniformly brown abdominal tergites distinguish it from M. luteoides Schmitz. The longer costa and hypopygium distinguish it from M. postorta Borgmeier. The species most closely resembles M. quadribrevis (see above), differing by their hypopygia. Haltere brown; labella not enlarged and with only a few small spinules below; three bristles on notopleuron.

Male

Frons brown, broader than long, with 50–60 hairs. Supra-antennal bristles very unequal. Antials almost level with and clearly closer to anterolaterals than to upper SAs, which are a little higher on frons. Bristles of middle row almost equally spaced and in an almost straight transverse row. Four short bristles on cheek and two long ones on jowl. Third antennal segment yellowish brown and with no SPS vesicles. Palps pale yellow with seven bristles, of which four are longer than breadth of palp, and as many hairs. The roughly heart-shaped, orange-brown, labrum at most 0.9× as wide as third antennal segment. Labella pale dusky yellow. Thorax orange-brown. Hairs of abdominal tergites sparse and short, but a little longer at rear margins and sides. Venter yellowish grey, with hairs below on segments 3–6 and a few on flanks at rear of 6. Hypopygium brown, but paler than T 6; with more yellowish hypandrial lobes and anal tube; and as figure 43. Lobe of right side of hypandrium much smaller and shorter than lobe of left side. Legs yellow, apart from tip of hind femur. All five fore tarsal segments with posterodorsal hair palisade, and segment 5 subequal to 4. Near-dorsal hair palisade of mid tibia extends about three-quarters of length. Mid tarsus similar to M. quadribrevis (figure 35A). Hairs below basal half of hind femur longer than those of anteroventral row of outer half. Wings 2.3–2.4 mm long. Costal ratios 3.0–3.1:1.8:1. Costal cilia 0.01 mm long. No hair at base of vein 3. Sc runs to R. Four bristles on axillary ridge. Veins yellowish brown to brown.

1

Membrane tinged yellowish grey.