This species is very similar in appearance, size (4-7 mm) and nesting habits to Formica fusca, but was firmly described and keyed by Yarrow in I954. Workers differ from those of F. fusca by the presence of short stubby hairs on the promesonotal dorsum which is usually bare in F. fusca, and there are good diagnostic differences in males and queens (Skinner & A llen 1990).
Editor's note. The original profile combined the two species F. fusca and F. lemani but this has been split by the editor to follow the Atlas style.
Formica lemani is abundant on high moorland in south-west England - Bodmin, Dartmoor, Exmoor, Mendips and Blackdown and on uncultivated land throughout Wales, northern England and Scotland as far as Hoy in Orkney. Excepting a doubtful record from Horsell Common, Surrey, it appears to be absent from the counties of south-east England - Hampshire and the Isle of Wight to Kent, Bedford and Northampton. Occasionally F. fusca and F. lemani have been found in close juxtaposition in the same habitat, but although dorsal hairs are sometimes sparse in a few worker samples, no true hybrids have been recognised.