Empis (Anacrostichus) verralli Collin 1927

Fig. 36.

Empis (Anacrostichus) verralli Collin, 1927: 21 (♂ and ♀). Type localities: UK, England: Snowdon (Carnarvon), Yorkshire; Scotland.

Empis (Anacrostichus) minor Frey, 1953: 35 (♂ and ♀). Type locality: Russia, Kamchatka: Ozernaya.

MATERIAL EXAMINED. USA. Alaska: Unalakleet [63°52′N 160°47′W], 29.vi.1961, B.S. Heming (1 ♂); same locality and collector, 23.vi.1961 (2 ♂♂), same data: 20.vi.1961 (7 ♂♂, 5 ♀♀), 29.vi.1961 (1 ♀), 5.vii.1961 (1 ♂, 1 ♀); same locality, 22.vi.1961, R. Madge (3 ♂♂, 5 ♀♀), 24.vi.1961 (1 ♀); Nome [64°30′N 165°24′W], 2.vii.1951, D.P. Whillans (1 ♂); same locality and collector, 20.vi.1951 (1 ♂), 15.vi.1951 (1 ♂), 6.vi.1951 (1 ♂), 18.vi.1951 (3 ♂♂), 19.vi.1951 (4 ♂♂), 12.vi.1951 (18 ♂♂, 1 ♀); Naknek [58°43′N 157°00′W], on tundra, 18.vii.1952, J.B. Hartley (1 ♂); same locality, 3.vii.1952, W. R. Mason (1 ♂).

REMARKS. It seems that this species was not described by the North American authors. Main differences of E. verralli from other Nearctic species of Anacrostichus are indicated in the key. Empis verralli was redescribed by Collin [1961] and Chvála [1994]. The wing venation of E. verralli is unstable (as both these authors have noted), including different degree of a reduction of the radial fork (R 4+5) and some other veins, extra crossveins, etc. In addition, the frons of the female sometimes is entirely pruinose (usually shiny on the middle).

DISTRIBUTION. Holarctic. In Eurasia, E. verralli is known from British Isles, extreme north of the European part of Russia, Siberia (including subarctic areas) and the Russian Far East [Shamshev, 2016]. In North America, E. verralli is known only from the western part of Alaska.