In the West-Palaearctic region, its range is rather strictly limited by the 69th and 70th parallels, i. e. to the taiga. In Asia, it occurs with different subspecies, with a wider latitudinal range, extending southwards beyond the limits of the taiga (Tkalcu, 1967). B. sporadicus is known from a large part of Fennoscandia. but common only in eastern Finland.
P. Rasmont