Cheilosia convexifrons Stackelberg

(Figs 1 A–G)

Cheilosia convexifrons Stackelberg, 1963: 4 .

Literature. Zimina (1968: 68); Violovitsh (1976: 335), (1982: 202); Barkalov (1983b: 85); Barkalov (1984: 85); Mutin & Barkalov (1999: 236).

Material examined. Russia: Yakutia: 1Ƌ, 1♀ Yakutia, Tokko Village on Chara River, 30 km SW of Olekminsk Town, 30– 31.05.1980, leg. A. Bagatshanova, ZMISEA; 1Ƌ , 4♀ Oktemtsy, 50 km SW of Yakutsk, 30.05–7.06.1976, leg. A. Bagatshanova, IBPC ; 2♀ Aldan River, Malyj Aldan Village, 28.05.1981, leg. A. Bagatshanova, IBPC ; 1♀ Magadan Province, mouth of the Kegali River, 17.06.1968, E. Levina, ZMISEA ; 1♀ Khabarovsk Territory: Komsomolsk-on-Amur, 16.05.1977, leg. V. Mutin, ZMISEA ; 1♀ 40 km NE of Komsomolsk-on-Amur, 13.05.1986, leg. V. Mutin, ZMISEA; 1Ƌ Primorskij Territory , 30 km N of Ternej Village, 26.05.1982, leg. V. Mutin, ZMISEA.

Diagnosis. Males of C. convexifrons are similar to C. morio but differ in the broader central knob (Fig. 1 A) and black hairs on disk of tergites II–III. In C. morio, the central knob is narrow despite of the very broad face (Fig. 3 A), and tergites II–III are covered with light hairs on disk. In female C. convexifrons, the eye margins and lateral stripes on the frons near the eyes are often orange-brown, and the mesonotum and abdomen are covered with short black hairs. In female C. morio, the eye margins and lateral stripes of the frons are black, and the mesonotum and abdomen are covered with yellow hairs.

Distribution. Russia: Yakutia and Far East.