Eumerus montanum Grković, Radenković & Vujić, 2017: 182

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 : 12-14

Eumerus montanum Grković, Radenković & Vujić, 2017: 182 , holotype: ♂, Montenegro:

“[ Durmitor Mountain], Komarnica , beside Pošćensko Lake [42°58′39.2"N, 19°04′15.9"E] ,

[1045 m.a.s.l.], 16.VIII 2015, leg. Vujić A.” (not examined).

SPECIMENS EXAMINED. Russia: Omskaya oblast: environs of Omsk City , 14. VI

1984, 1 ♂ (A. Barkalov); Novosibirskaya oblast : 29 km SW of Karasuk Town, Biological station of ISEA, 12–19.VI 1988 , 11♂, 1♀ (I. Kharitonova); same place, 8–22.VI 1982; 6.VII

1990; 28.VI 2002; 6.VII 2004; 4.VII 2004, 4♂, 4♀ (A. Barkalov); Ordynskij District , 25.VIII

1958, 1♂ (O. Ivanovskaya); Altai Republic: Gorno-Altaisk Town , 22.VI 1983 , 1♂ (A.

Barkalov); Cherga settlement, 20-30.VIII 1992, 1♂ ( V. Marchenko); Terekta settlement ,

3.VII 1973, 1♂ (L. Levina); Republic of Buryatia: Baikal Nature Reserve , Tankhoi, 26. VI

1980, 1♂ (A. Barkalov) [ SZMN] .

DIAGNOSIS. This species belongs to the Eumerus strigatus species-group (Speight et al., 2013; Speight, 2016; Grković et al., 2017). All members of the species-group have the following characters: eyes with short sparse pile; male with holoptic eyes; ventral surface of metatibia with a shallow, longitudinal ridge carrying short, black procumbent setulae in the basal half of its length; abdomen black with pairs of lunulate-shaped oblique maculae of silver-grey pollinosity on 2nd, 3rd and 4th terga.

Eumerus montanum is extremely similar to E. consimilis , E. sogdianus and E. strigatus ,

all of which have the metafemur without a baso-ventral tubercle, large oval basoflagellomere in females and pale pile on the 8th sternum in males. The male of E. montanum is easily distinguished by the shape of the genitalia and the form of the 4th sternum (Figs 12, 13). The upper lobe of surstylus long and broadened apically. Posterior margin of 4th sternum with deep cut, similar to E. sogdianus .

view; 2, 4 – female, dorsal view; 3 – male, lateral view; 5 – wing membrane. Scale bars: 1–4

= 1 mm; 5 = 0,2 mm.

The female of E. montanum does not differ essentially from E. consimilis , E. sogdianus and E. strigatus . In addition to the original description of E. montanum, Grković et al. (2017)

gave a table for diagnosing related species, which is unsuitable for determining the above-

mentioned species except for a single character: the form of the ocellar triangle. The female

E. montanum has an isosceles ocellar triangle, longer than wide. The female E. sogdianus has a similar state of this character, whereas those of E. consimilis and E. strigatus have equilateral ocellar triangles. A second character of this table may be useful in distinguishing females,

namely longer pilosity on the ventral surface of the metafemur (Grković et al., 2017); the pile length in E. montanum is about half as long as the depth of the metafemur, whilst that of E.

consimilis, E. sogdianus and E. strigatus is shorter, only about 1/3 the depth of the metafemur.

view; 8 – female head, dorso-frontal view; 9 – male, lateral view. Scale bars: 6, 7, 9 = 1 mm;

8 = 0,5 mm.

Siberian specimens of E. montanum have variable shapes of the ocellar triangle, whereas the pattern of pollinosity on the frons and occiput is rather constant. The pollinosity of the frons forms narrow silver strips along the eyes, whilst the medial part of the frons is shiny

(Fig. 10). However, this character is found only among small females of E. strigatus from the

Far East; normally they are more or less densely pollinose between the lateral silver stripes

( Fig. 19 ). Female E. sogdianus have less developed pollinosity on the medial part of the frons ( Fig. 21 ).

REMARKS. Males of this species have not been found together with other males of the strigatus species-group in the same places, and therefore females collected simultaneously are considered by us to be conspecific.

DISTRIBUTION. Russia (new record): West Siberia (Omskaya oblast, Novosibirskaya oblast), Altai, Buryatia. – Southern Europe ( Montenegro, Greece).

Figures

Figs 19–22. Eumerus ssp.: 19 – female head of Eumerus strigatusm, dorsal view; 20–21