The general arranging of information in the book is aimed at handiness for identification. We therefore list synonymies, material examined and the bibliography at the end. Throughout we follow systematic and not alphabetical order. This is to encourage curators to do the same with the collections under their care as too many synonyms in large genera went undetected for decades simply because of alphabetical ordering. Genera, subgenera and species are therefore treated in the same sequence as they key out in the various phylogenetic cladograms. In the case of subspecies, however, the nominal subspecies is always treated first. Diagnostic information (comparative notes, diagnoses, detail drawings and distribution maps) of every species or subspecies is provided together on one page. The introduction chapters provide short backgrounds limited to considerations that are relevant to our taxonomic decisions. They are certainly not intended as exhaustive treatments of the various themes, as speculations on historical geography and phylogeny alone could fill a volume without, however, contributing much to the taxonomy.