Megaselia bilobulus, DISNEY, 2003

DISNEY, R. H. L., 2003, Tasmanian Phoridae (Diptera) and some additional Australasian species, Journal of Natural History 37 (5), pp. 505-639 : 532-534

Megaselia bilobulus sp.nov.

(figure 12A, B)

Material

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

P    : male, same data as holotype, except (25-8) ( UMZC); male, Fern Tree, Grays Road, 147°15∞E, 42°57∞S (grid ref. 203474), 540 m altitude, 7–17 August 2000 ( RHLD —25-42) ( UMZC) .

Etymology The name refers to the paired lobes at the rear of the hypandrium.

Diagnosis

The costal index being 0.40–0.46 and the mesopleuron having two to five hairs and either with or without a short bristle as well, this species could be assigned to any of the four groups II– V in Borgmeier’s (1967a) keys. In group II it runs to couplet 7 (p. 202), where its brown thorax and abdominal tergites plus the front basitarsus not being dilated will distinguish it from the two species of this couplet. In group III it will run to couplet 5 lead 1 (p. 205), but is immediately distinguished from M. sodalis (Brues) by the antials being clearly closer to the eyes than to the upper SA bristles. In group IV it will run to couplet 15 lead 2 (p. 206), but the near-dorsal hair palisade of mid tibia extends less than two-thirds of length, whereas in M. textilis Brues it extends about three-quarters of length. In group V it runs to couplet 2 (p. 206), but differs from M. turbidipennis Borgmeier by having a much longer anal tube, longer costal cilia (0.10–0.12 mm long) and darker brown halteres and legs. Its hypopygium distinguishes it from subsequently described species running to these same couplets. Other diagnostic features are dense, fine, microsetae on frons; pale yellowish brown palps; three bristles on the notopleuron; scutellum having an anterior pair of very small hairs and a posterior pair of bristles; anal tube subequal in length to midline length of epandrium; left side of latter with more than a dozen short hairs as well as a clearly differentiated longer hair; hypandrium with a pair of short lobes; anteroventral hairs of outer half of hind femur being clearly longer than those below basal half; hind tibia lacking differentiated anterodorsal hairs; vein 3 without hair at base; and vein Sc not ending in R.

1

Male

Frons brown and wider than long. Antials almost level with upper SA bristles but a little lower than anterolaterals. Lower SAs almost as long and as robust as upper SAs. Bristles of median row almost equally spaced or preocellars slightly further apart than either is from a mediolateral. All four bristles in an almost straight transverse row or POs slightly higher on frons than MLs. Three bristles on cheek and three or four on jowl. Antennae brown and third segments without SPS vesicles. Pale yellowish brown labrum only about 0.6× as wide as third antennal segment. Pale labella with only scattered hairs below. Abdominal tergites with short hairs and only the posterolaterals a little differentiated on T 6. Venter greyish brown with hairs below on segments 4–6 and 0–2 near spiracles on 5 and 6. Hypopygium brown, including anal tube, and as figure 12B. Legs pale brown with paler tarsi. Front tarsus with posterodorsal hair palisades on segments 1–4 only and segment 5 only slightly longer than 4. Hind femur as figure 12A. Hind tibia with about 14 weakly differentiated posterodorsal hairs. Wing 1.3–1.9 mm long. Costal index 0.40–0.46. Costal ratios 2.99–3.47:1.18–1.39:1. Costal cilia 0.11–0.14 mm long. Veins brown and membrane only lightly tinged brownish grey. With two axillary bristles, the outer being shorter and weaker than costal cilia and inner one shorter and weaker still.