This paper describes a new species of Arctorthezia Cockerell (Hemiptera: Coccoidea: Ortheziidae) from the Palaearctic region. The specimens were extracted from forest litter in the collections of Muséum d'histoire Naturelle de Genève, Switzerland, using Berlese funnels. Three further species, Arctortheziacataphracta (Olafsen), Arctortheziaoccidentalis (Douglas) and Arctortheziapseudoccidentalis Morrison, are redescribed and re-illustrated. The genus Arctorthezia now contains five species. An identification key, diagnostic illustrations, photographs of unmounted females and new locality records of the Arctorthezia species currently known are provided.
Keywords: Ensign scale; Palaearctic Region; Switzerland; archaeococcoids; distribution; taxonomy.