| abstract | Erythraeus (Parerythraeus) thomasi sp. nov. is described and illustrated based on specimens collected from Finland. Parerythraeus Southcott, 1946 stat. nov., previously synonymized with Erythraeus Latreille, 1806, is considered a subgenus of Erythraeus. Thirteen species, including E. (P.) thomasi, are included in this subgenus, and a differential diagnosis is provided for the 12 adequately described species. A key to all known species of Erythraeus (Parerythraeus) is also provided. |