Cheilosia, , sensu Sack, 1932

Barkalov, Anatolij V., 2020, New data on the genus Cheilosia Meigen (Diptera, Syrphidae) from Central Asia with descriptions of two new species and a key to the ‘ group C’, Zootaxa 4860 (2), pp. 243-256 : 253

Key to the ‘group C’ species of Cheilosia from Central Asia

Since there have been significant changes in the taxonomy of the Cheilosia species of the ‘group C’ (haired eyes, bare face and hind margin of scutellum without strong setae: subgenera Montanocheila and Cheilosia s. str.) (Barkalov & Peck 1997), we offer a new version of the key that includes all species described since 1997 from Central Asia. Drawings of the structure of male genitalia can be found in the publications indicated for each species.

1 Hind margin of scutellum without black bristles, sometimes with black hairs the same length and width as other hairs...... 2

- Hind margin of scutellum with some black bristles.......................................................... 22

2 Postpedicel elongated, its width less than eye-margin width at the broadest part. Length 9.7–12 mm. Hypopygium: see Barkalov & Peck (1997b)........................................... C. rufiventris Peck, 1969 (male, female with bared eyes)

- Postpedicel with a different shape, its width broader or equal to eye-margin width.................................. 3

3 Postpedicel orange or dark red, maximally darkened at antero-dorsal angle........................................4.

- Postpedicel black, or black with lighter postero-ventral angle.................................................. 14

4. Tibiae and tarsi except segment 5, yellow.................................................................. 5

- At least tibiae in central part and segment 1 and 5 of hind tarsi, black............................................. 7

5 Inner angle between veins M 1 and R 4+5 equal to 90° ( Fig. 4G ).................................................. 6

- Inner angle between veins M 1 and R 4+5 acute ( Fig. 4H ). Length 9.8–12 mm. Hypopygium: see Barkalov & Peck (1997b)........................................................................... C. xanthella Barkalov & Peck, 1997

6 Body covered with long dense orange hairs. Big, robust flies 10.9–13 mm. Hypopygium: see Barkalov & Peck (1997b)............................................................................ C. heptapotamica Stackelberg, 1963

- Body covered with short, not dense, white or light-yellow hairs. Slender flies with an elongated body. Length 8.6–10.5 mm ............................................. C. urbana ampla Barkalov & Peck, 1997 (female, male see couplet 12)

7 Frons with light hairs.................................................................................. 8

- Frons with black, or black and yellow hairs................................................................. 9

8 Face and frons shiny without dusting, eye-margin brownish. Bigger specimens: 14–15.8 mm. Hypopygium: see Barkalov & Peck (1997b).................................................................... C. nudifacies Becker, 1921

- Face and eye-margin with grey dusting, eye-margin black. Smaller specimens: 9.7–10.7 mm. Hypopygium as in Figs 5 A–C............................................................................. C. zinchenkoi Barkalov, 2005 .

9 Eyes with black hairs................................................................................. 10

- Eyes with white or yellow hairs......................................................................... 12

10 Hind margin of scutellum with light hairs, or light and black hairs.............................................. 11

- Scutellum with only black hairs. Length 11.7–13 mm. Hypopygium as in Figs 4 D–F............ C. kirgizorum Peck, 1971

11 Frons very swollen, frontal angle more than 120°, scutum and scutellum with black hairs medially. Length 12.2 mm. Hypopy- gium as in Figs 5 G–I....................................................... C. stackelbergiana Barkalov, 2005

- Frons not very swollen, frontal angle 90–95°, scutum and scutellum with yellow hairs medially. Length 7.7–9.3 mm. Hypopy- gium as in Figs 5 D–F.......................................................... C. dzhungarica Barkalov, 2008

12 Fore tarsi black dorsally. Length 11.4 mm. Hypopygium as in Figs 2 E−G........................... C. vadimi sp. nov.

- At least segments 1−2 of fore tarsi yellow dorsally.......................................................... 13

13 Frons with dense grey dusting, scutum with only yellow hairs, segments 2–4 of tarsi yellow. Length 8.6–10.5 mm. Hypopygium: see Barkalov & Peck (1997b).............. C. urbana ampla Barkalov & Peck, 1997 (male, female: see couplet 6)

- Frons without dusting, scutum with black hairs in posterior part. Length 8–11 mm. Hypopygium: see Barkalov & Peck (1997b).......................................................................... C. thalassica Peck, 1971

14 Tibiae completely or mostly yellow, segments 1–2 of mid tarsus yellow......................................... 15

- Tibiae mostly and tarsi dorsally black, sometimes tips of tarsal segments yellowish................................ 16

15 Eyes with black or dark-brown hairs. Length 11–12 mm. Hypopygium: see Barkalov & Peck 1997b.. C. grossa ( Fallén, 1817)

- Eyes with light hairs. Length 12.6 mm. Hypopygium: see Barkalov & Peck (1997b)..... C. erratica Barkalov & Peck, 1997

16 Scutum with only yellow hairs. Length 13.5–14.5 mm .............................. C. kiritshenkoi Stackelberg, 1963

- Scutum with black, or black and yellow hairs.............................................................. 17

17 Eyes with black hairs................................................................................. 18

- Eyes with light hairs.................................................................................. 20

18 Tergites of abdomen with black hairs, sometimes with yellow hairs on central part of tergites II–III................... 19

- Tergites of abdomen with light hairs. 12.3 mm. Hypopygium as in Figs 1 D–F................... C. teneripilosa sp. nov.

19 Superior lobe of the hypandrium with elongated basal part ( Fig. 3B ). Length 13.5 mm. Surstylus and aedeagus as in Figs 3A, C............................................................................... C . milkoi Barkalov, 2005

- Basal part of superior lobe of hypandrium shorter ( Fig. 3E ). Surstylus and aedeagus as in Figs 3D, F... C . zlotini Peck, 1969

20 Scutum with only black hairs. Length 9.4–13.8 mm. Hypopygium as in Figs 4 A–C............................................................................................ C. vtorovi Peck, 1969 (male, female—see ‘group D’)

- Scutum with light-yellow hairs in anterior half............................................................. 21

21 Posterior half of the scutum with short black hairs and longer yellow hairs double the length........................................................................................... C. zinchenkoi Barkalov, 2005 (see couplet 8)

- Scutum with only yellow hairs all of the same length. Length 7–9.5 mm .... C. aerea Dufour, 1848 (part, see also ‘group D’)

Figures

FIGURE 1. Cheilosia teneripilosa sp. nov. A: head of male, lateral view. B: head of female, dorsal view. C: pedicel and postpedicel of male, lateral view. D: superior lobe of hypandrium, lateral view. E: aedeagus with apodeme. F: surstylus and gonocercus, lateral view; l. p., left process of superior lobe; r. p., right process of superior lobe. Scale bar in mm.

FIGURE 2. Cheilosia vadimi sp. nov. A: head of male, lateral view. B: head of female, dorsal view. C: pedicel and postpedicel of male, lateral view. D: pedicel and postpedicel of female, lateral view. E: surstylus and gonocercus, lateral view. F: superior lobe of hypandrium, lateral view. G: aedeagus with apodeme. Scale bar in mm.

FIGURE 3. Cheilosia milkoi (A–C) and Cheilosia zlotini (D–F). A, D: surstylus and gonocercus, lateral view. B, E: superior lobe of hypandrium, lateral view. C, F: aedeagus with apodeme. Scale bar in mm.

FIGURE 4. Cheilosia vtorovi (A–C), Cheilosia kirgizorum (D–F), Cheilosia heptapotamica (G) and Cheilosia xanthella (H). A, D: surstylus and gonocercus, lateral view. B, E: aedeagus with apodeme. C, F: superior lobe of hypandrium, lateral view. G, H: tip of wing. Scale bar in mm.

FIGURE 5. Cheilosia zinchenkoi (A–C), Cheilosia dzhungarica (D–F) and Cheilosia stackelbergiana (G–I). A, E, G: surstylus and gonocercus, lateral view. B, D, I: aedeagus with apodeme. C, F, H: superior lobe of hypandrium, lateral view. Scale bar in mm.