Chelipoda didhami Published 2007, sp. n.

31. Chelipoda didhami sp. n.

[Figs. 70, 115, 116]

Type material. Holotype ♂: New Zealand, South Is., NN? Castle Rock Hut, 1220m, yellow pan trap in tussock herbfield, 14–16/i/1986, JWE [NZAC]. Paratypes: 1♂, 3♀, same data as holotype [NZAC, NMWC].

Etymology: named in honour of Raphael Didham whose systematic fieldwork has yielded much important information of New Zealand Empididae.

Description. Male: length = 2.0mm.

Head: black dusted greyish, face paler; subspherical, ocellar triangle mid way between antennae and vertex; eyes separated on face by about 0.5X width of scape; ocl stronger than verticals; upo short, more or less congruent with inner vertical (vt1); lpo rather strong, diverging away from posterior eye margin below and merging with scattered bristles of similar strength on lower occiput posteriorly.

Antenna: (Fig. 116) brownish on basal segments (pedicel particularly dark); postpedicel rather paler, 6X as long as wide, swollen basally, narrowing abruptly, becoming evenly narrowed in distal 0.8; arista 0.3X as long as postpedicel; scape 1.5X as long as wide with a distinct dorsal seta. Palpi elongate-oval, yellowish with a small distinct apical bristle.

Thorax: ground colour dark reddish brown (possibly blacker in life, the type series is preserved in alcohol and colour may have faded); extremely faint indications of 2 paler stripes on pleura. Dusted grey, scutum with narrow median stripe and wider lateral stripes more shining. All setae black; dc1 very short and spine-like; dc2, dc3, pprn, unp, sa, and sct well developed, lnp smaller.

Legs: yellowish, C 1 with strongly marked stripe anteriorly, apical tarsal segments dusky. C 1 0.9X as long as thorax, only small bristly hairs anteriorly. F 1 as long as C 1, moderately and evenly inflated, widest 0.4–0.5 from base. 2 rows of bristles beneath F 1; a strong av spine 0.3 from base continued basally by weaker bristles and distally by 8–10 rather evenly sized short black denticle-like spines; pv series of spines irregularly linear, rather short, a strong ventral bristle 0.1 from base. T 1 0.85X length of F 1, gently curved, slightly narrowed apically; a linear series of minute black adpressed denticles ventrally; at2 as long as at3.

Wing: with veins brown, membrane faintly darkened; venation simple, cell cup hardly closed, vein A 1 strong about end of CuA 2 but very weak basally.

Abdomen: brown, tergites with weak setae on posterior margins, strongest on segment 5. Terminalia (Fig. 70) yellowish brown, reflexed dorsally; hypandrium not fused with epandrium, epandrial lobes separate, rather convex, slightly overlapping hyp below, bearing strong dark posteroapical setae; hypandrium inverted heart-shaped, almost divided into two lobes below, the intervening area between lobes membranous and very weakly chitinized; subepandrial process long, narrow, evenly curving anteriorly on distal part; cerci free, at least apically, with 2 long and several shorter yellowish apical setae; postgonite apically spathulate, virtually transparent and weakly sclerotized; phallus curving, strongly reflexed posteriorly before tip.

Description. Female: similar to male but slightly larger (2- 0–2.5mm). Antenna (Fig. 115) with postpedicel much shorter, 3.5X as long as wide, swollen basally, more evenly pointed apically; arista slightly longer than postpedicel. Setae of lower occiput and lpo finer. Thorax with dc1 longer, 0.3X as long as dc2. F 1 rather more inflated, ventral chaetotaxy longer and more numerous particularly in pv series which is also more strictly linearly arranged. Abdominal setae much shorter, strongest basally, not on tergite 5; terminal papillae brown, slender with long pale hairs.

Comments. C. didhami is a dark species in the C. trepida -group with only faint indications of thoracic markings and two rows of setae beneath F 1. Cell cup is closed (although A 1 is very faint basally) and the postpedicel is elongated in both sexes. C. didhami is an alpine species presently known only from a single tussock herbfield in the South Island of New Zealand.