Neohemigaster angustifrons Galinskaya & Shatalkin

Galinskaya, Tatiana V. & Shatalkin, Anatole I., 2013, Neohemigaster Malloch, 1939 and Pterogenia Bigot, 1859 (Diptera: Platystomatidae) from eastern Eurasia, with the description of four new species, Zootaxa 3666 (2), pp. 267-285 : 277

Neohemigaster angustifrons Galinskaya & Shatalkin sp. nov.

( Fig. 7 )

Type material. Holotype 3: “РВ, плато Тэйнгуен, стационар Буон Лыой, 7.I.1986, в/др., 22А, 19.II.1986, Есенин А.В.” [ Vietnam, plateau Teynguen, station Buon Lyoy, 7.I.1986, 22А, 19.II.1986, Esenin A.V.] (ZMUM).

Diagnosis. The new species resembles N. ornata in having similar pattern of mesonotal stripes and wing with the stigmatal band separated from the r-m vein. N. angustifrons sp. nov. differs from N. ornata by the absence of median facial and median epistomal spots and by the broad pleural yellow stripe stretching from anterior margin of anepisternum to katepimeron.

Description of the holotype. Male. Head yellow ( Figs 7 c,d). Head ratio (length:height:width) = 1:2.2:2.6. Frons: relatively narrow, about 0.3 as wide as head; yellow with pair of black triangular spots, widely separated from each other and narrowly separated from eye margin, between these spots and black ocellar triangle microtrichose areas are situated; small black spot merging with the posterior margin of microtrichose areas, a little before anterior ocellus; evenly covered with short and thin black setulae, at eye margin these setulae are yellow. Ocellar triangle black. Eye bare, 1.8 times as high as wide. Gena 0.2 times as high as eye. Lunule yellow, black setulose. Parafacial very narrow at level of antennal groove, smooth. Facial ridge broad, yellow; its ventral margin with group of yellow (ventral) and black (dorsal) hairs, not assembled in linear series. Face yellow with one pair of black spots in the point of bend of frontogenal suture. Margin of peristomal cavity with pair of lateral brown spots. Occiput black in upper half and yellow in lower half; postgena with brownish spot merging with posterior margin of eye, above its inferior angle. Scape brownish, covered with rather dense black setulae. Pedicel yellow, covered with yellow setulae, except dorsal and ventro-marginal setulae black. First flagellomere brown, narrowly yellow at base, 2.3 times as long as wide. Arista brown, yellow at base, covered with relatively long hairs, arista feathering 0.6 times as wide as first flagellomere. Palp yellow, darkened at the apex, covered with blackish setulae. Proboscis yellow.

Setae: 1 o vt, 1 i vt; orb, oc and poc absent; gn well-developed, black.

Thorax mostly yellow, with blackish-brown stripes and spots ( Fig. 7 b). Mesonotum narrowly black colored anteriorly, between postpronotal lobes; two wide longitudinal stripes begin from this dark marking, every stripe broken into three spots: anterior spot сonnects with transverse suture; medial spot oval; posterior spot slightly arcuate, extending to yellow scutum. Postpronotal lobe with round black spot. Notopleuron narrowly black colored. Anepisternum with black stripe at the upper margin; anepimeron, katatergite, anatergite and subscutellum black; katepisternum mostly black, yellowish at the upper margin and in the lower part ( Fig. 7 a). Scutellum yellow with two brown oval spots.

Setae: 1 pprn, 2 npl, 1 psut spal, 1 very strong pal and 1 ial, 1 weak dc; 4 rather strong sctl at posterolateral corner and posterior margin of scutellum; 1 anepst; kepst lacking.

Legs blackish-yellow. Fore femur with brown mark anteriorly, from the basis to the middle. Mid and hind femora with wide brown spot ventrally, in upper third. Tibiae with brown ring in upper third. Tarsomere 1 yellowish-white; tarsomeres 4–5 brown.

Wing hyaline, with numerous brownish-grey irregular spots ( Fig. 7 e). Stem R vein without dorsal setulae. Vein R 1 setulose dorsally from base to apex. Vein R4+5 setulose dorsally on 9/10 of its length, and bare ventrally. Basal part of vein Cu1 (bounding cup cell from anteriorly) setulose dorsally. Halter yellow; stem before knob brownish. Calypters white.

Abdomen black. Tergite 3 widely yellow colored laterally.

Body length 5.5 mm. Wing length 5.8 mm.

Female not known.

Etymology. The species name is derived from the latin “angustus”, narrow, and “frons”, forehead.

Figures

FIGURE 7. Neohemigaster angustifrons sp. nov., male holotype; a—habitus, lateral view, b—head and thorax, dorsal view; c—head, lateral view; d—head, anterior view; e—wing.