Eumerus roborovskii Stackelberg, 1952: 398

Mutin, V. A. & Barkalov, A. V., 2018, New data on the hover-flies of the genus Eumerus (Diptera: Syrphidae) from Russia, Far Eastern Entomologist 363, pp. 11-20 : 15-16

Eumerus roborovskii Stackelberg, 1952: 398 , holotype: ♂, China: «Бугас у Хами, на ЮВ

от ТЯнь- ШанЯ, 7 IX 1895 (Роб[оровский], КоЗлов)» [ZIN] (examined).

SPECIMENS EXAMINED. Russia: Zabaykalsky krai: 70 km SW of Chita, Sokhondo,

30.VII 1984, 1♀ ( V. Makarkin); Tyva Republic: Dyttykh-Khem River , 12 km SE Samagaltai settlement , 9.VII 2013, 1♂, 1♀ (M. Proshchalykin & V. Loktionov ); the same place, 17.VII

2014, 1♀ (M. Proshchalykin, A. Lelej & V. Loktionov) [ PMC] .

DIAGNOSIS. This species belongs to the E. strigatus species-group and is more similar than E. funeralis Meigen, 1822 is to Eumerus consimilis , E. montanum , E. sogdianus and E.

strigatus in not having a baso-ventral tubercle on metafemur. The visibly narrower basoflagellomere of E. roborovskii is the main difference from these other species; the male basoflagellomere is 2.5 times longer than wide (Fig. 15), and the female basoflagellomere is 1.5

times longer than wide ( Figs 8 , 16). For example, male E. sogdianus and E. strigatus have almost oval basoflagellomeres, with a ratio of length:width of 4:3. The female basoflagellomere of E. sogdianus is rather rounded, its length is slightly more than its width. The female E.

strigatus has a rounded basoflagellomere. Like E. strigatus , the female E. roborovskii has an equilateral ocellar triangle, differentiating them at least from European specimens of E.

sogdianus and E. montanum with their isosceles ocellar triangles. The male genitalia of E.

roborovskii are similar to E. strigatus , but the inner tooth on the upper lobe of surstylus is poorly developed (Fig 18). In addition, male E. roborovskii have the posterior margin of the

4th sternum sharply v-shaped with a small medial notch (Fig. 17).

FEMALE (nova). Body length 6,8–8,0 mm, wing length 5,5–6,0 mm.

Head. Face weakly widened ventrally, black, dense greyish pollinose, except for gene and epistoma under tentorial groove shiny, with erected white pile. Frons, vertex and occiput behind ocellar triangular weakly shiny black except greyish pollinose in the form of narrow stripes of along eyes, with short erect white or yellowish pile, sometimes with a few black pile near antenna base and black pile on ocellar triangle. Minimal width of frons more than

1/4 the width of the head. Ocellar triangle equilateral (Fig. 14). Scapus and pedicel black;

basoflagellomere mainly dark brown except baso-ventral part red or red-brown, distinctly longer than its width with a ratio of length:width of 3:2 ( Figs 8 , 16); arista black. Eyes with very short sparse white pile.

Thorax. Postpronotum brightly shiny. Mesonotum black, with bluish or steel reflections,

with short semi-erect yellowish pile dorsally and longer white pile laterally. Scutum with more or less broad submedial vittae of greyish pollinose before transverse suture. Legs:

coxae and metatrochanter black; pro- and mesotrochanter brown; femora black with reddish apex; metafemur thickened, with longer white pile ventrally, as long as 1/2 of the femur depth, with a pair of spinose ridges apico-ventrally; tibia mainly black, except basal 1/3

reddish, metatibia with baso-ventral ridge of shallow procumbent black setulae; tarsi black dorsally and reddish ventrally, basotarsomere of metatarsus shorter than total length of subsequent tarsomeres. Wings translucent, membrane without visible spots and lacking in microtrichia.

Abdomen a little broader than mesonotum, black with three pairs of oblique grey pollinose maculae on 2nd, 3rd and 4th terga; maculae on 3rd tergum rather bigger than others; 2nd and

3rd terga with white erect pile laterally; 4th tergum in the main and 5th tergum entirely with -

whitish pile; other parts of abdomen with shorter adpressed black pile.

REMARKS. The species was described by Stackelberg (1952) on the basis of two males from China (Xinjiang Uygur Autonomous Region) and Uzbekistan ( Kattakurgan Region ) .

Later Peck (1988) noted this species for other territories of Central Asia.

DISTRIBUTION. Russia (new record): Zabaykalsky krai, Tyva Republic. – Kirghizia,

Tajikistan, Uzbekistan, China.

Figs 10–18. Eumerus ssp.: 10–13 – E. montanum ; 14–18 – Eumerus roborovskii : 10, 14 –

head, dorsal view; 11, 16 – female antenna, lateral view; 15 – male antenna, lateral view; 12,

17 – male 4th sternum, ventral view; 13, 18 – male genitalia, lateral view.

Figures

Figs 6–9. Eumerus roborovskii: 6 – female, lateral view; 7 – female abdomen, dorsal