Pachylophus lacteibasis, 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 : 14

Pachylophus lacteibasis sp. n.

Diagnosis. A small species distinctive in having the wing grey fumose with a strongly contrasting cream-coloured costal cell.

Description. Female. Head deeper than long, yellow, the parafacial and gena silvery dusted throughout, at narrowest point equal to one and a half times width of arista; frons slightly longer than wide, rounded anteriorly and only slightly projecting in front of eyes; frontal triangle brownish black, completely undusted, extending five sixths of the way from ocellar prominence to anterior margin of frons, slightly convex sided, with concave surface, broadly flanked on either side by greyish dust that contrasts with the narrow band of silvery grey dust flanking the eye; frons posteriorly somewhat darkened, but the slight elevation bearing the vertical setae dirty yellow; occiput obscurely infuscate on upper half, with distinct lateral flange; face dull grey dusted; antenna with postpedicel rather short, yellow, black on upper half and arista uniformly haired. Thorax yellow, but black on entire dorsal surface apart from the apex of scutellum medially, dark grey dusted apart from a pair of paler grey dorsocentral lines that are more evident presuturally, punctured, the scutellum roundedly trapezoid with a single pair of widely separated marginal setae; other scutal setae are a single dorsocentral, one postalar and a single posterior notopleural preceded by a hairlike anterior notopleural; pleuron entirely shining anterior to the posterior one third of anepimeron, but katepisternum weakly silvery grey dusted in front of mid coxa, brown on a large triangular patch on katepisternum, on upper, lower and hind margins of anepisternum, on anepimeron, lower part of meron and on mediotergite. Legs dirty yellow to brownish yellow; sensory area of hind tibia reduced to a minute pore at one third of its length. Wing greyish fumose with dark brown veins, apart from the strongly contrasting cream-coloured costal cell and veins containing it; distance between crossveins equal to twice length of posterior crossvein; squama yellowish with white fringe; haltere yellow. Abdomen yellow with tergites brown and weakly grey dusted; cerci yellow.

Length about 2.7mm, of wing 2.1mm.

Male resembling female in all but the postabdomen.

Material: Holotype ♀, SOUTH AFRICA: E . Cape Prov. , Van Staadens Pass, v.1959, B. & P. Stuckenberg; Paratypes 1♂ 2♀, same data as holotype (all in NMP) .

A female is chosen as holotype purely because it is the only specimen in perfect condition, the other specimens showing some psocid damage . A further female from Mozambique, labelled "Port . East Africa , Zambezi River Delta, Chinde, P.J. Usher " in NMP is not included in the type series. It is a dirty specimen, but differs from the type series in being much darker, the pleura being completely dark apart from the obscurely yellow upper margin of the katepisternum, the femora black and the mouth margin infuscate. This specimen would run to P. lugens in the above key, but differs from that species in wing and haltere colour and in its deeper gena.