Cheilosia ( Cheilosia ) grossa ( Fallén, 1817 )

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 : 66-67

Cheilosia ( Cheilosia) grossa ( Fallén, 1817)

Fig. 33

Eristalis grossa Fallén, 1817: 53 .

Cheilosia grossa Meigen, 1822 [sic] – Gujabidze 2002: 246.

Cheilosia grossa – Barkalov 1993: 718. — Mengual et al. 2020: 17.

Differential diagnosis

Cheilosia grossa is a large species ( 11–12 mm) with dense body pile, pilose eye, bare face, bicoloured legs and posterior margin of scutellum without setae. Identified from other species occurring in the Caucasus having this set of characters except C. balu by the black postpedicel (at least basoventrally orange in the others). Easily distinguished from C. balu by the yellow metafemur (with black ring in C. balu ), black pile on eye (brown or yellow in C. balu ; Fig. 11B, D), scutum with yellow pile (in the male of C. balu with black pile, in the female with field of black pile in posterior part) and pruinose sterna (predominantly shiny in C. balu ). Very similar to C. pseudogrossa , but face bare (pilose in C. pseudogrossa ). For more differences, see at the Differential diagnosis of C. pseudogrossa .

Material examined

Not collected in 2018, but collected in 2023.

GEORGIA – Samtskhe-Javakheti • 2 ♀♀; Sakire; 41.7301° N, 43.3306° E; 1820 m a.s.l.; 10 May 2023; F. Van de Meutter leg.; FMT, ZFMK-TIS-8027941 .

Genetics

In our NJ tree we recover a cluster of three species with high support (BS = 100%), C. albipila , C. grossa and C. pseudogrossa . The two DNA sequences of C. pseudogrossa group together with high support (BS = 99.7%), as well as the barcodes of C. grossa (BS = 100%), except for three (Scandinavian) sequences that are placed within the C. albipila cluster. The study of the available photographs in BOLD of those three specimens of C. grossa (KWi-089, KWi-090 and NORSY471) do not question their identification.

Distribution

Palaearctic and Uttah Pradesh in northern India. Within the Caucasus reported from Georgia for the first time.