Formica yessensis WHEELER, 1913

Formica truncorum var. yessensis WHEELER, 1913 [type investigation]

The taxon was described by FOREL (1901) under the infrasubspecific name Formica rufa r. truncorum var. yessensis FOREL, 1901 from Sorachi, some 100 km ENE of Sapporo, Hokaido. Investigated was one type worker from MHN Genève labelled by A. Forel “ Formica truncicola v. yessensis For Type ” and carrying a printed label “Sorachi Prov. Ishikari Yesso V. 1899. Mus.em. 24.XI.1899 ”. The specimen shows below average setae length on eyes and no setae on dorsum of scape, and extensor profile of hind tibia but is in any character within the range of variation known from the Palaearctic population of F. truncorum . For a more detailed argumentation in favor of this synonymization, see below under taxonomic comments.