Cheilosia venosa Loew

Stahls, Gunilla & Barkalov, Anatolij V., 2017, Taxonomic review of the Palaearctic species of the Cheilosiacaerulescens-group (Diptera, Syrphidae), ZooKeys 662, pp. 137-171 : 154-157

Cheilosia venosa Loew Fig. 11

Cheilosia venosa Loew, 1857:603; Barkalov and Ståhls 1997:63.

Chilosia venosa : Becker 1894:356; Sack 1932:106; Šuster 1959:70.

Type locality.

‘Oesterreich’ [sic] [Austria].

Type material studied.

Lectotype ♂, pinned, with genitalia dissected in microvial, in MNB, here designated to fix the concept of Cheilosia venosa Loew and to ensure the universal and consistent interpretion of the same. The original descriptions is only for the male sex. The lectotype is labelled: 'Austria, Schiner’ [handwritten, faded inc], 'Coll. H. Loew’, 'Zool. Mus., Berlin’, 'Lectotype Cheilosia venosa Loew, Ståhls & Barkalov des.'.

Description.

♂: Face in anterior view moderately divergent from level of antennal insertion to lower mouth edge, with lower part not very prominent, with band of pollinosity (Fig. 11A). Facial knob prominent (nose-like). Parafacia with pollinosity, on lower part shining patch, slightly more than 1/2 the width of basoflagellomere. Frons shining, rather swollen, with black and white pile. Frontal angle ≈ 90°. Lunula dark-brown to blackish. Antennal pits confluent (occasionally only narrowly confluent). Vertical triangle with black pile. Eye-contiguity nearly equal to length of frons without lunula. Basoflagellomere small, rounded, brown to reddish brown. Arista short, thickened, clearly pubescent (Fig. 11B).

Scutum densely punctated, shining, with long, erect yellow pile, medially a transverse band of predominantly black pile. Scutellum on hind margin without (occasionally with some) black bristles. Postalar callus with two bristles. Pleura pollinose, with long black and yellow pile. Dorsal and ventral pile patches of katepisternum only narrowly connected anteriorly. Legs black, knees sometimes yellow, tibia sometimes black ringed. Apical half of posterior surface of mesofemur and basal part of anterior surface of metafemur with long black pile (Fig. 12A). Halter yellow. Wing with all crossveins infuscated, R4 + 5 distinctly curved (Figs 11I, 12A). Wing completely microtrichose. Abdomen shining, with pollinosity on middle part of tergites I–III. Tergites with long, erect, yellow pile laterally, and black short erect pile medially. Sternites I pollinose, II–IV shining. Hypopygium as on Fig. 11 F–H.

♀: Face shining with fine pollinosity on the sides. Parafacia comparatively narrow, pollinose. Frons moderately broad, shining (Fig. 11D), with yellow and black pile (Fig. 11E). Basoflagellomere, small, rounded, black to brownish, with sensory pit (Fig. 11 C). Arista short, with dense, short pile, almost on whole length of arista. Scutum shining, with long, erect yellow and black pile of equal length. Pleura slightly pollinose. Scutellum margin without black bristles. Otherwise as the ♂.

Size. Body length 9-11 mm.

Additional material studied. Austria 1 ♂ ‘Österreich, Tirol, Seefelder Joch, 2 050m, 15.VII.1969, v.d. Goot’ [in ZMA], 1 ♂ 'Austria, Brauer’ [MNB], 1 ♂ 'Austria, Schiner’ [MNB]; Switzerland 1 ♀ 'Helvetia, GR, Lenzerheide, Parpaner Rothorn, 2 850 m, 14.VII.96, B. Merz’ [ETH]; Italy 1 ♀ ‘Südtirol, Val di Planol, 2 000-2 400 m, 7.VII.1988, C. Claussen’ [in MZH], 1 ♀ 'Stelvio Pass, 1 600-2 000 m, 22.VII.1988, Daccordi’ [in MZH], 1 ♀ 'Valle Aurina , Bolzano, Val d. Vento, 2 400 m, 11.8.1987, Daccordi’ [in MZH].

Distribution.

Austria, Italy*, Germany, Romania, Switzerland*.