Megaselia species A

DISNEY, R. H. L., 2003, Tasmanian Phoridae (Diptera) and some additional Australasian species, Journal of Natural History 37 (5), pp. 505-639 : 593-595

Megaselia species A

(figure 46)

This species appears to be only known in the female sex and is probably an undescribed species.

Material

Female, Tasmania, Hobart, Battery Point, De Witt Street, garden, 1–11 January 1992 (Disney—25-7) ( UMZC) .

Diagnosis

The combination of scutellum with anterior pair of minute hairs and posterior pair of bristles; mesopleuron bare; costal index>0.43 but <0.5; forked vein 3; hind tibia lacking differentiated anterodorsal hairs; frons with dense microsetae; costa not swollen; brown abdominal tergites being normal; haltere knob yellow; and antials midway between upper supra-antennal and anterolateral bristles; takes this species to couplet 55 on p. 89 of Borgmeier’s (1967b) keys. However, at couplet 54 lead 1 one must allow for an error. Costal section 1 is not longer than sections 2+ 3 in M. semihyalina Beyer. I have remounted a paratype male (in the Museum Koenig, Bonn) and it confirms that the original description is correct in giving 1<2+3. Species A has 1>2+3 and its hind femur is yellow with a brown tip, but it is brown in M. semihyalina . M. mediocris Borgmeier lacks the brown tip to its yellow hind femur and its Sc vein is vestigial, whereas in species A it is present, but pale, and ends before R. The femora of M. nana (Brues) are brown. Females of subsequently

1

described species running to the same couplets either have extensive yellow areas on the abdominal tergites or the hind femora are mainly a darker brown. Third antennal segment lacks SPS vesicles; notopleuron with two bristles; abdominal sternum 8 with paired elongated lobes at rear margin; cercus with a single long hair, the rest being short.

Female

Frons brown, broader than long, with 70–80 hairs. Lower SA bristles fine and only 0.3–0.5× as long as upper pair. Antials about midway between upper SAs and anterolaterals and level with upper SAs. ALs a little higher on frons. Bristles of middle row almost equally spaced and in nearly straight transverse row. Three or four short bristles on cheek and two longer ones on jowl. Third antennal segment brown. Palp pale yellow lightly tinged brown, especially on basal part of stem, with eight short bristles (only two or three being a little longer than breadth of palp) and as many fine hairs. Pale brown labrum about 1.2× as wide as third antennal segment. Labella narrow, pale whitish yellow with narrow brown band above, and almost no spinules below. Thorax brown. Abdominal tergites with minute hairs except at rear margins of T5–T7 (figure 46C). Venter greyish brown, with only minute hairs below segment 3, with similar ones plus hairs on 4–6 and longer hairs at rear of segment 6. Sternite 7 as figure 46B. T8 about 1.2–1.3× as long as broad and hind margin about three-quarters as wide as front margin. Posterolateral lobes of sternum 8 and cerci as figure 46A. Apart from tip of hind femur, the legs are essentially yellow very lightly tinged brown. Front basitarsus slender, only first four segments with posterodorsal hair palisade, and segment 5 distinctly longer than 4. Hair palidsade of mid tibia extends about three-quarters of length. Hairs below basal half of hind femur longer than those of anteroventral row of outer half. Ten to 12 differentiated posterodorsal hairs on hind tibia. Wing 1.8–1.9 mm long. Costal index 0.47. Costal ratios 3.51:2.27:1. Costal cila 0.09 mm long. Vein Sc straight, faint and ending before R. Small hair at base of vein 3. Axillary ridge with two 1

bristles that are longer than costal cilia. Veins yellowish brown, but 7 pale. Membrane only lightly tinged grey.