20. Leptothorax corticalis (Schenck, 1852) Fig. 97.

Myrmica corticalis Schenck, 1852:100.

Worker. Pale reddish brown with the head and gaster usually darker, antennae unicolorous brown; alitrunk and head finely longitudinally striate but general appearance shining. Propodeal spines reduced to very short denticles; petiole node triangular in profile with dorsal area reduced or absent. Length: 2.5-3.2 mm. Queen. As worker, length 3.5-4.0 mm.

Male. Alitrunk smooth with no striae at sides; antennae pale brown; segments 2-3 only very slightly longer than broad. Length: 3.0 mm.

Distribution: Very local in Sweden: Vstm., Upl. (Forsslund, 1957a); 01. (Douwes, 1976 a). - Not found in Britain. - Range: Central Europe, rare, recorded only from Spain, France, North Italy, Austria, Czechoslovakia, Germany and Belgium.

Biology. This is a little known rare Central European species. It is a bark inhabitant and Forsslund (1957a) found it nesting in old oak trees inhabited by Lasius brunneus (Latr.). Only worker samples were seen. Douwes (1976a) records workers taken on Gland on oak and in a fallen branch. The species appears to be closely related to L. nylanderi which has similar habits.