Empis leucostigma Bezzi, 1909

Rafael, J. A. & Câmara, J. T., 2012, Revision of Neotropical species of Empididae (Diptera) described by Mario Bezzi. XI. The species described in Empis Linnaeus, Zootaxa 3488, pp. 63-79 : 70-71

Empis leucostigma Bezzi

( Figs. 32–40, 81)

Empis leucostigma Bezzi, 1909: 356 ; Melander, 1928: 160 (checklist); Collin, 1933: 231 (citation); Smith, 1967: 22 (catalogue); Yang et al., 2007: 135 (catalogue).

Diagnosis. Scape, pedicel, legs and abdomen reddish-brown; thorax dark brown to black, opaque, densely grey pruinescent; scutum with four matte-black stripes in anterior view; tiny proepisternal setae; wing elongate, light brown; halter and both thoracic spiracles yellow; sternite 8 sclerotized.

Re-description. Holotype female. Body length 5.7 mm; wing length 6.6 mm. Dichoptic; frons black, grey pruinescent dorsally, grey-yellow ventrally, visible at certain angles, wider than ocellar tubercle, twice higher than wide, with 7 small, proclinate setae. Ocellar tubercle black, grey pruinescent. Ocellus glassy, yellow; with divergent anterior ocellar setae, 3 small posterior setae. Face bare, slightly higher than wide, slightly divergent towards proboscis, grey pruinescent, except ventrally, on protuberant part, with narrow shiny brown band. Postcranium ( Fig. 32) dark brown to black, densely grey pruinescent; with uniserial to biserial postocular row of setae, superior ones longer ( Fig. 33); occipital setae restricted to dorsal half, misaligned. Gena with slender setae and postgena with shorter setae. Antenna ( Fig. 32) with scape and pedicel reddish-brown; postpedicel velvety matte-black, coniform, 1.5X longer than scape and pedicel together, twice as long as stylus. Proboscis ( Fig. 32) about 2.5X longer than head; labrum yellow, shiny; labium brown. Palpus brown with distinct slender setae.

Thorax ( Fig. 34) dark brown to black, densely grey pruinescent. Scutum, in anterior view, with four matteblack stripes; two paramedian stripes, between acrostichal and dorsocentral rows, narrower and extending slightly beyond transverse suture; two lateral stripes between dorsocentral and supra-alar rows, extending from postpronotal lobe to level of postalar callus. Anterior and posterior spiracles yellow. Chaetotaxy: antepronotum with 1 robust and various small apparently biserials; 1 robust, 4–5 weak postpronotals; 2–3 proepisternals; roughly 15 small and slender proepimerals; roughly 10 uniserial acrostichals, slightly out of alignment; roughly 10 biserial dorsocentrals, posteriormost seta longest and more robust; 1 presutural intra-alar; 2 small postsutural intra-alars just posterior to transverse suture and 1 posterior; 4 small aligned presutural supra-alar; 4 postsutural supra-alars, posteriormost seta robust; 1 robust and 1 weak postalars; 3 robust posterior and 8 weak anterior notopleurals; 4 scutellars, shorter basal and subapical pairs intermixed with longer; 15–17 laterotergitals.

Legs ( Figs 35–37) reddish-brown, grey pruinescent; all legs with some setae slightly longer than background setae, especially on antero- and posterodorsal rows, and apical antero- and posteroventral setae of tibiae and tarsomeres; hind coxa thicker and shorter than both anterior coxae.

Wing ( Fig. 81) elongate, light brown, pterostigma brown, veins dark brown; base of costal vein with robust seta (not represented in figure). Vein R 1 bare above, not dilated towards apex. Halter yellow.

Abdomen reddish-brown, subshiny, grey pruinescent, with pruinescence restricted to posterior margin of tergites when viewed from posterior angle; tergites with marginal setae slightly shorter than laterals. Sternites concolorous with tergites.

Terminalia. Tergite 8 shorter than respective sternite ( Fig. 38); sternite slightly acute, sclerotized medially and apically, with small clear central circle ( Fig. 40). Tergite 10 with deep basal sinus ( Fig. 39) and respective sternite with shallow basal sinus ( Fig. 40); genital fork with arms U-shaped ( Fig. 39); cercus broken.

Male. Unknown.

Geographical record. Peru.

Material examined. HOLOTYPE ♀. “ PERU, Cuzco, 08.iv.1905, 3700–4200 m ” (SMT).

Holotype condition. Left postpedicel and left hindleg missing. Right wing partially damaged. Left wing in microslides. Terminalia in microvial with glycerin.

Discussion. The female specimen of E. leucostigma is identified as part of group II in Collin’s (1933) key through the same couplets presented above for E. angustipennis . Further in the key it ends in couplet (15) of E. variabilis Bigot, 1857 due to “thorax with four contrasting dark stripes”. They are not conspecific because E. leucostigma has three stripes and a reddish-brown abdomen (yellow at apex in E. variabilis ), a light brown wing (almost hyaline in E. variabilis ), and 4 scutellar setae (6–8 in E. variabilis ).