Cheilosia ( Montanocheila ) balu Violovitsh, 1966

Bot, Sander, Mengual, Ximo, Meutter, Frank Van de & Skevington, Jeffrey H., 2025, Review of the genus Cheilosia Meigen, 1822 (Diptera: Syrphidae) from the Caucasus, with the description of 14 new species, European Journal of Taxonomy 1023, pp. 1-181 : 26-28

Cheilosia ( Montanocheila) balu Violovitsh, 1966

Fig. 11

Cheilosia balu Violovitsh, 1966: 54 .

Differential diagnosis

The lack of setae along the posterior margin of the scutellum, in combination with a pilose eye, bare face, and bicoloured legs distinguishes Cheilosia balu from many other Cheilosia . As a member of the subgenus Montanocheila , it has a brown pattern on the wing and in the male the genitalia is distinct, apical sclerite of distiphallus with two pairs (anterior and posterior) of lobes, for drawings of the male genitalia, see Violovitsh (1966). Within Montanocheila it is distinguished from the other members of that subgenus occurring in the Caucasus by the black postpedicel ( Fig. 11B, D) (at least basoventral corner of postpedicel orange in the other species); the male has black pile on scutum ( Fig. 11A, predominantly or entirely yellow in the other species) and the female has a field of predominantly black pile medially on posterior half of scutum (entirely with yellow pile or with few scattered black pile only in the other species). Given the black postpedicel, C. balu is similar to C. grossa , but metafemur with black ring ( Fig. 11A) (yellow in C. grossa ), eye has yellowish or brown pile (black in C. grossa ) and sterna are predominantly shiny (pruinose in C. grossa ).

Material examined

GEORGIA – Mtskheta-Mtianeti • 1 ♂; Stepantsminda ; 42.5317 ° N, 44.5183° E; 2772 m a.s.l.; 31 Jul. 2001; J.-H. Stuke leg.; ZFMK, ZFMK-DIP-00058266 • 3 ♀♀; same data as for preceding; ZFMK, ZFMK-DIP-00058265 , ZFMK-DIP-00058267 , ZFMK-DIP-00058268 .

Remarks

Reported from the Caucasus and Georgia, for the first time. Compared to specimens from the Altai, differences could be detected, e.g., face narrower (resulting in the male having angle of approximation of eyes <90° instead of ca 90°), base of metafemur anteroventrally with scattered long pile shorter than width of metafemur (Altai specimens with scattered long pile longer than width of metafemur) and sterna II–IV shiny (dull in Altai specimens). Given that we lack genetic data from the Caucasus, that we could not study subspecies C. balu jugorica Barkalov, 1993 from North Siberia, and that we have one male from the Caucasus only, we for now consider the differences to be variation within C. balu .

Distribution

Russia: Northern Siberia (westwards just into European Russia), Altai, the Caucasus in Georgia.