Fig. 24 in A taxonomic revision of the Palaearctic members of the Formica rufa group (Hymenoptera: Formicidae) - the famous mound-building red wood ants

Fig. 24: Position of the type samples of Formica major NY- LANDER, 1849 (MA) and Formica constricta KARAVAJEV, 1929 (CO) in a principal component analysis considering 58 nest samples of Formica polyctena (black squares) and 27 nest samples of Formica aquilonia × polyctena or backcrosses (white dots). The F. polyctena sample deeply placed within the hybrid cluster is aberrant and cannot be a hybrid for zoogeographical reasons. Seven phenotypic characters were considered.