Megaselia andrewi, DISNEY, 2003

DISNEY, R. H. L., 2003, Tasmanian Phoridae (Diptera) and some additional Australasian species, Journal of Natural History 37 (5), pp. 505-639 : 529-531

Megaselia andrewi sp. nov.

(figure 11A–D)

Material

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

P    : female, same data as holotype ( RHLD —25-8) ( TMH) ; male, female, Hobart, Battery Point, De Witt Street, garden, 1–11 January 1992 and 10–12 June 1995 ( RHLD —25-21, 25-39) ( UMZC) . 6 males, 2 females, Fern Tree, Grays Road, 147°15∞E, 42°57∞S (grid ref. 203474), 540 m altitude, 7–17 August 2000 ( RHLD — 25-41-45) ( TMH, UMZC, CSIRO) .

Etymology The species is named after my son-in-law, Andrew Climie.

Diagnosis

The combination of scutellum with a pair of small hairs and a pair of bristles; a mesopleuron with hairs plus one or two moderate bristles; costal index>0.44 but <0.50; costal cilia 0.10–0.12 mm long; no differentiated anterodorsals on hind tibia; haltere knob dusky yellow to pale brown; supra-antennal bristles clearly unequal; wing length <3.0 mm; moderately short anal tube; and yellowish brown legs; will take this species to couplets 14 or 20 on p. 203 of Borgmeier’s (1967a) keys, depending on the costal index being <0.48, or couplets 39–41 on p. 204 if this index is>0.48. It is immediately distinguished from M. albiclavata Borgmeier (misprinted as M. albiclava in the key) by its much darker wing veins (which are readily seen with a ×4 lens when viewing against a white background). It differs from M. purificata Borgmeier by its shorter costal cilia (<0.14 mm long) and in lacking a differentiated strong bristle-like hair on the left side of the epandrium. If the costal cilia are treated as short (<0.1 mm long) then this species readily runs to couplet 39 on p. 204, then (depending on the costal index being <0.5 or 0.5 or more) to couplets 41 and 43. It is immediately distinguished from M. castanea Bridarolli by costal section 1 being clearly longer than sections 2+3; and from M. longinqua Bridarolli by the frons being clearly broader than long. Its distintict vein Sc will distinguish it from the species of couplet 43. Some specimens of M. impariseta will run to couplet 40 but are distinguished in the key below. Three subsequently described Oriental species, also running to these couplets, are all distinguished by their very different hypopygia. Frons clearly broader than long and with dense, but fine, microsetae; upper supra-antennal bristles only 0.2× width of frons apart; male with dusky yellow to yellowish brown palps, which are somewhat inflated and with relatively short bristles; anal tube shorter than midline length of epandrium, which has weaker hairs than those at rear of sternum 6 and lacks differentiated bristles; left hypandrial lobe well developed and bare on distal quarter at least.

Male

Frons brown. Antials closer to anterolaterals than to upper SAs, the latter being very slightly higher on frons. Bristles of middle row almost equally spaced and in an irregular transverse row. Third antennal segment yellowish brown, with darker arista, and with numerous SPS vesicles (about as large as sockets of lower SAs). Palps pale yellowish brown and as figure 11B. The yellowish brown labrum at most two-thirds width of third antennal segment. The pale labella with only scattered hairs below. Thorax mainly orange-brown but darker on top of scutum and scutellum. Notopleuron with three bristles. Mesopleuron with 10–15 hairs plus one or two clearly differentiated bristles. Abdominal tergites brown wth well-developed hairs, which are stronger at rear margins of T 2– T 6, those on T 6 being conspicuously longer (figure 11A). Hypopygium mainly brown with yellowish brown anal tube and as figure 11A. Legs pale yellowish brown apart from brown mid coxae, dorsal edges of hind tibia and femur, and tip of latter. Front tarsus slender, the lengths of the segments progressively diminishing and only one to four with a posterodorsal hair palisade. Near-dorsal, longitudinal hair palisade of mid tibia extends almost to tip. Hairs below basal half of hind femur clearly longer than those of anteroventral row of distal half. Hind tibia with about a dozen posterodorsals, of which at least nine are robust. Wing 1.52–2.13 mm long. Costal index 0.46–0.50. Costal ratios 3.36–4.20:1.81–2.32:1. Membrane tinged brownish grey. All veins brown. Sc not quite reaching R. Two 1 axillary bristles about as strong as costal cilia. A minute hair at base of vein 3.

Female

Head similar to male, except palps not inflated and width of labrum subequal to that of third antennal segment. Thorax as male, but mesopleuron with 7–16 hairs plus one or two bristles. Abdominal tergites brown, with T 2 being the widest and the following tergites being progressively narrower. T 5– T 8 as figure 11D. Venter brownish grey and with hairs below on segments 3–6. Cerci whitish yellow,>3× as long as broad, with about 10 hairs, of which the posterior (inner) pre-apical is longer than rest. Internally there are four rectal papillae, an ill-defined furca (sternite 9) as figure 11C, and a rounded to pear-shaped Dufour’s crop mechanism. Legs similar to male. Wings 1.9–2.7 mm long. Costal index 3.0–4.0:1.5–2.1:1. Costal cilia 0.11–0.14 mm long. Otherwise as male.

Natural history

Gravid females had one to three eggs, which when mature measure 0.94× 0.35 mm.