This species is easily confused with Formica cunicularia, especially in the worker caste. The queen's red and black patched trunk provides a guide (see Donisthorpe, 1927, for a black and white illustration giving a good impression of this feature). Live workers appear distinctive with legs darker than the trunk and with a matt black gaster; they swarm rapidly out of the nest in large numbers to attack a disturber.

This species was taxonomically confused as a variety of Formica fusca L. or as a synonym of F. rufibarbis until revised by Yarrow (1954). Formica cunicularia includes two variety names of F. fusca: vars. glebaria and rubescens given to workers which are not entirely black as is typical of F. fusca, but which have some red on the sides of the head (glebaria) or with reddish legs and thorax as well (rubescens). They are clearly not as shiny black when compared with F. fusca and are distinguished from F.… Read more