The present Guide covers 54 species with their accepted subspecies. A large number of synonyms are cited too. The present Guide is something like a supplement of the book The Genus Colias Fabricius, 1807, which allows to get a quick overview about this genus and to re-organize a collection. Here the taxa are treated species by species, each one with its subspecies, while in the above cited Colias monograph they are treated extensively in alphabetical order. Every reader who is interested in more information will find it in the Colias monograph.
About the 'Guide to the Butterflies of the Palearctic Region' series
This is a series about the butterflies of the whole Palearctic, from North Africa and Europe to China and Japan. Each volume of the series will cover 80-100 species with full colour illustrations, genitalia drawings, distribution, taxonomy, variations and diagnostic characters. Many well-known lepidopterists worldwide are contributing to this project, with the final result being a series of booklets with each one covering a subfamily, a tribe or a group of genera with a total of 50 to 100 species. It is anticipated that, when completed, this series will comprise over 30 volumes of work covering the Satyridae, Papilionidae, Pieridae, Nymphalidae, Lycaenidae, Hesperidae, and other families.