Megaselia quattuorbrevis Disney 2008, sp. nov.

(Fig. 10–11)

In the keys of Borgmeier (1967b) this will run to couplet 68, Lead 2 on page 90. Not only is its costal section 1 greater than sections 2+3, but it is immediately distinguished by the elongated fifth tarsal segments of the middle legs. However, the latter feature is shared by the subsequently described M. gotoi Disney running to the same point. Two Tasmanian species, M. quadribrevis Disney and M. tetrabrevis Disney, possess similarly elongated fifth tarsal segments on the middle legs. The hypopygia immediately distinguish these four species from each other.

The name refers to fourth tarsal segments of the middle legs being shorter than the fifth segments.

Male. Frons brown, clearly broader than long, with 68–74 hairs and dense but fine microsetae. SAs unequal, the lower pair being shorter. The antials lower on frons than upper SAs, and about midway between ALs and latter, or a little closer to an AL bristle, which are about level with upper SAs. Pre-ocellars a little further apart than upper SAs and slightly further apart than either is from a mediolateral bristle, which is very slightly higher on frons. Cheek with 2 bristles and jowl with two longer ones. The subglobose postpedicels slightly dusky straw yellow and without SPS vesicles. Palps straw yellow but in part with a very light brownish tinge, at most a quarter the width of a postpedicel, with 5 bristles and 6 hairs. Labrum pale and about 2.8x as wide as a palp. Labella light brown, together about as wide as a postpedicel, and with only a few short spinules below. Thorax straw yellow, being paler on sides (apart from brown spot on pteropleuron). Three notopleural bristles and no cleft in front of these. Mesopleuron bare. Scutellum with an anterior pair of hairs (about as strong as those in middle of scutum) and a posterior pair of bristles. Abdominal tergites brown with longest hairs towards sides of T2 and posterolaterally on T6 (Fig. 11). Venter whitish grey, and with a few hairs on segments 3–6. Hypopygium with brown epandrium but largely pale straw yellow hypandrium, with a pale anal tube with a light brown tinge, and as Fig. 11. The larger left lobe of the hypandrium is bare in its outer half, but the shorter right lobe has small hairs extending almost to the tip. Legs straw yellow (apart from brown patch on mid coxa). Fore tarsus with posterodorsal hair palisade on segments 1–5 and 5 slightly shorter than 4. Dorsal hair palisade of mid tibia extends almost entire length. The fifth tarsal segment much longer than fourth segment (Fig. 10). Hairs below basal half of hind femur longer than those of anteroventral row of outer half. Hind tibia with eight differentiated posterodorsal hairs restricted to lower two thirds, and spinules of apical combs simple. Wings 1.6–1.7 mm long. Costal index 0.48–0.49. Costal ratios 5.1–5.2: 3.0–3.1: 1. Costal cilia (of section 3) 0.07 mm long. No hair at base of vein 3. With two axillary bristles, the outer being longer than costal cilia. Sc not reaching R1. Thick veins light brown, thin veins 4 and 5 grey, 6 dark grey and 7 pale and obscure in basal half. Membrane lightly tinged grey (just evident to naked eye when viewed against a white background). Haltere knob brown.

Material. Holotype male, Australia, New South Wales, Tweed Heads, 10 The Quarterdeck, garden, water trap, 27 June 2008, R. H. L. Disney (AMS, 25–61).