The queens fly from the middle of June to the end of August, and the males from early July to mid-August. Workers of this species are very rarely encountered. The reason for this may be the shortness of the season and also that the queen B. hyperboreus can usurp the nests of B. polaris (=arcticus) and B. jonellus. It is therefore regarded as a facultative inquiline.
Taxonomic status: The identity of B. arcticus (Quenzel) has been uncertain (Baker, 1996a:16, believes that it may have been published by accident rather than design). Warncke (1986) listed B. arcticus (Quenzel) as conspecific with B. lapponicus without any explanation. Presumably this was because B. lapponicus is extensively pale on the dorsum, although the pale pubescence is differentiated into yellow and red areas and much of it is much paler than Quenzel's description. I agree with Løken (1973) that, from the original description and the illustration (no type specimen is known to exist), B. arcticus (Quenzel) is most likely to be conspecific with B. hyperboreus, which has the pale pubescence uniformly brownish yellow.
Nomenclature: The name B. arcticus has rarely been used for this species in preference to B. hyperboreus, and perhaps only as a misidentification of B. arcticus Kirby (see e.g. Franklin, 1913; Richards, 1931a). Løken (1973) considered B. arcticus (Quenzel) to be a nomen oblitum, so she continued to use the name B. hyperboreus. However, nomina oblita are not supported for a publication of this date by the present Code (ICZN, 1999: Article 23.12), although it allows that B. arcticus (Quenzel) could be suppressed by use of the Plenary Power.
Although B. arcticus is the oldest available name for the present interpretation of this species, the name B. hyperboreus has been in common use for the species since 1950 (e.g. Løken, 1973; Milliron, 1973a; K. W. Richards, 1973; Svensson & Lundberg, 1977; Hurd, 1979; Pekkarinen, 1979; Pekkarinen et al., 1981; Reinig, 1981; Rasmont, 1983; Pekkarinen & Teräs, 1993). It is suggested that, in the interests of stability (ICZN, 1999: Article 23), an application be made to ICZN to use its Plenary Power to suppress an unused senior synonym (ICZN, 1999: Article 78), in order to confirm the usage of B. hyperboreus as the valid name (in prep.). See the comments on B. polaris Curtis.