Pachylophus aristalis, Deeming, 2018

Deeming, John C., 2018, A revision of the Afrotropical species of Pachylophus Loew (Diptera: Chloropidae) and some related Ovoviviparous genera, Zootaxa 4482 (1), pp. 1-51 : 5-7

Pachylophus aristalis sp. n.

( Plate 2, Figs 4, 5)

Diagnosis. A black species with yellow head and legs, black undusted frontal triangle, black thorax, the greater part of the pleura heavily grey dusted, the wing long and narrow and the arista (Fig. 4) having the sum of the lengths of the first two segments equal to the length of the third.

Description. Male. Head as long as deep; frons hardly projecting in front of eye; frontal triangle straightsided, extending almost to anterior margin of frons, with the whole field anterior to ocellar prominence concave; occiput black throughout and dark grey dusted; combined parafacial and gena one third of height of eye, bearing numerous short pale setulae, it and the face silvery grey dusted throughout; palpus yellow; antenna infuscate, with basal half of postpedicel dirty yellow on inner surface; postpedicel rounded, deeper than long, its dorsoapical angle a right angle. Thorax black, dirty yellowish brown on prosternum and lower part of meron, heavily grey dusted, shining on cervical sclerites, anterior half of anepisternum and that part of katepisternum adjacent to it, the extreme lower margin of anepisternum and its raised posterior rim; scutum heavily punctured, the dusting slightly darker between the dorsocentral lines, along the intraalar lines and onto scutellum; setae very weak, the 2 notopleurals equally fine, the dorsocentral and postalar indistinguishable from the surrounding short fine setulae and the single pair of marginal setae on the apically rounded scutellum fine and widely separated. Legs including coxae dirty yellow, the mid and hind femur each with a tiny shining black apical spot both anteriorly and posteriorly; tarsomeres slightly infuscate, especially the more apical ones; sensory area of hind tibia conspicuous and occupying middle one third of its length. Wing long and narrow, the discal cell long and narrow, the distance separating crossveins equal to three times the length of the posterior crossvein; squama grey with fringe grey; haltere with stem black and knob creamy yellow.

Abdomen yellow with tergites black and heavily dark grey dusted.

Length about 3.5mm, of wing 3.5mm.

Female unknown.

Material: Holotype, ♂, SOUTH AFRICA: E . Cape Province, Van Staalens Pass , v.1959, B. & P. Stuckenberg ( NMP) ; Paratype, ♂, ANGOLA: (A 24) 3 mls. N. Santa Comba, 7.iii.1972, BMSAE ( NHMUK) .

Note. The structure of the arista is much more like that of the genus Platycephalisca Nartshuk 1959: 472 than that of Pachylophus . The short head and absence of a prominent facial carina excludes its inclusion in the former genus. The paratype has the postpedicel dirty yellow on all but a dorsal line, the first aristal segment slightly shorter and the anepisternum dusted only in upper posterior corner.

Figures

PLATE 1. Figs 1–3, Pachylophus pellucidus Becker; 1, female, habitus; 2, puparium, anterior spiracle; 3, puparium, posterior spiracles.