This monophyletic group of nymphaline butterflies inhabiting northern hemisphere are characterized by a jagged outline of their wings and the ability to survive the winter months as adults in an obligatory hibernaldiapause, hiding in various shelters (e.g., crevices, hollows, cavities, even unheated buildings). The signature mark of all butterflies is the cryptic colour and maculation of the ventral (under) side of their wings, serving to conceal the hibernating butterfly against the substrate on which it rests.
Korshunov, 1995. [Butterflies of the Asian part of Russia. A handbook] Dnevnye babochki Aziatskoi chasti Rossii. Spravochnik.:202 pp. (re: Roddia)
Kudrna, O. & J. Belicek, 2005. The Wiener Verzeichnis, its authorship, publication date and some names proposed for butterflies therein. Oedippus 23: 1-32. (re: Schiffermüller names)
Linnaeus, C. 1758. Systema Naturae per Regna Tria Naturae, Secundum Clases, Ordines, Genera, Species, cum Characteribus, Differentiis, Symonymis, Locis. Tomis I. 10th Edition Syst. Nat. (Edn 10). (re: N. antiopa, P. c-album, P. c-aureum, I. io, N. polychloros, A. urticae)