Apsona Westwood, 1876

Winterton, Shaun L., 2012, Review of Australasian spider flies (Diptera, Acroceridae) with a revision of Panops Lamarck, ZooKeys 172, pp. 7-75 : 10-11

Apsona Westwood, 1876 Figs 2A4-6

Apsona Westwood, 1876: 510 - Bigot 1890: 317; Hutton 1901: 27; Paramonov 1955: 19; Schlinger 1966: 112; Schlinger and Jefferies 1989: 375. Type species: Apsona muscaria Westwood, 1876 by monotypy.

Diagnosis.

Body length: 7-9 mm. Colouration metallic green; head width slightly smaller than thorax width, hemispherical; postocular ridge and occiput rounded; three ocelli; posterior margin of eye rounded; eye pilose (dense); position of antenna on frons nearer to ocellar tubercle; eyes contiguous above and below antennal base; palpus present; proboscis longer than head length; flagellum shape elongate, tapered apically, apex lacking terminal setae; scapes separate; subscutellum not enlarged, barely visible; tibial spines absent; pulvilli present; wing hyaline, markings absent; costa circumambient, costal margin straight apically in both sexes; humeral crossvein present; radial veins curved towards wing anterior margin; R1 not inflated distally; pterostigma and cell r1 membranous, not ribbed; R2+3 present; R4+5 present as forked petiolate veins; cell r4+5 bisected by 2r-m, basal cell narrow elongate, closed; 2r-m very short, joining M1 to stem R4+5; R4 without spur vein; medial vein compliment with M1, M2 and M3 present (M3 fused with CuA1); discal cell closed completely; M1 and M2 usually not reaching wing margin; cell m3 present; CuA1 joining M3, petiolate to wing margin; CuA2 fused to A1 before wing margin, petiolate; wing microtrichia absent; anal lobe well developed; alula absent; abdominal tergites smooth, rounded; abdomen shape greatly rounded, inflated, conical posteriorly.

Included species.

Apsona muscaria Westwood, 1876.

Comments.

Apsona is a monotypic genus endemic to New Zealand and can be readily differentiated from all other Panopinae based on the lack of tibial spines. Apsona shows little relationship to the rest of the Australasian Panopinae and shows remarkable similarity to the New World genus Eulonchus Gerstaecker, 1856, sharing numerous characteristics such as metallic green colouration, antennal shape, dense eye pilosity, elongate mouthparts, eyes contiguous below antennal base and absence of an alula ( Paramonov 1955).