The genus Polyergus is characterized, and all valid species reinstated and re-described, and five new species described, based on morphometric, ecological, host-association, and biogeographic characteristics. Polyergus contains 14 species: 3 Palaearctic, 11 Nearctic. The rufescens group comprises western Eurasian rufescens Latreille 1804 including its former eastern subspecies tianschanicus Kuz...