Helle Osten Sacken, 1896

Winterton, Shaun L., 2012, Review of Australasian spider flies (Diptera, Acroceridae) with a revision of Panops Lamarck, ZooKeys 172, pp. 7-75 : 47-51

Helle Osten Sacken, 1896 Figs 3A56-59

Helle Osten Sacken, 1896: 16 - Hutton 1901: 28; Paramonov 1955: 21; Schlinger and Jefferies 1989: 376. Type species: Acrocera longirostris Hudson, 1892: 56 by monotypy.

Diagnosis.

Body length: 4.0-6.0 mm [male], 6.0-7.0 mm [female]. Body shape strongly arched; colouration non-metallic (brown or black); head size slightly narrower than thorax width, shape sub-spherical; postocular ridge and occiput rounded; three ocelli, anterior ocellus reduced in size; posterior margin of eye rounded; eye apilose; position of antennae on head near middle of frons; eyes contiguous above antennal base, not contiguous below antennal base; palpus present; proboscis greater than head length; flagellum stylate, apex with terminal seta; postpronotal lobes enlarged, medially contiguous to form collar; subscutellum enlarged; legs not elongated; wing markings absent; costa ending near wing apex, costal margin straight; humeral crossvein absent; radial veins straight or curved towards wing anterior margin; R1 inflated distally at pterostigma; pterostigma and cell r1 membranous, not ribbed; R2+3 present; R4+5 angled anteriorly approximately midway; cell r4+5 bisected by 2r-m, basal cell very narrow elongate, closed; 2r-m joining M1 to R4+5; cell r4+5 present, narrow elongate, closed (open apically when 2r-m rarely absent); crossvein 2r-m present (rarely absent);R4 without spur vein; medial vein compliment with M1, M2 and M3 present (M3 fused with CuA1); discal cell closed completely; medial veins not reaching wing margin; CuA1 joining M3, petiolate to margin; CuA2 fused to A1 before wing margin, petiolate; wing microtrichia absent; anal lobe well developed; alula well developed; abdominal tergites smooth, rounded; abdomen shape elongate, narrow cylindrical or conical (male), or rounded and inflated (female).

Included species.

Helle longirostris (Hudson, 1892); Helle rufescens Brunetti, 1926.

Comments.

Helle is an endemic genus to New Zealand that is closely related to Schlingeriella , the only other philopotine genus in the region ( Gillung and Winterton 2011; Winterton et al. 2007). Characteristics supporting this closerelationship include thickening of wing vein R1 at the pterostigma, elongate mouthparts, apilose eyes, 2r-m absent (rarely in Helle ) and R4+5 angled anteriorly approximately half way along vein. Helle can be differentiated from all other philopotine genera based on the relatively complete wing venation, inflated R1 at pterostigma, palpi present and apilose eyes.

Key to Helle species