A systematic treatise on the Chrysididae, a globally distributed family of wasps, also known as gold wasps (for their bright metallic colours) or cuckoo wasps (for their parasitic habits). Some 3,000 valid species have been named and are arranged in 84 genera and 4 sub-families. This book is the first re-evaluation of their taxonomy since 1889 and its four main goals are: to provide a worldwide overview of the family, with re-classification of the generic and higher taxa; to summarize previously published information; to indicate problems in need of further study; to give detailed synonymic species lists for each genus, where synonymy refers to scientific names used in different nomenclature systems to designate the same species. Discussions for each tribe and sub-family include ancestral characteristics, phylogenetically important characters and a corresponding cladogram, keys to genera, and relationships amongst taxa. Generic discussions include generic synonymy and diagnostic features, relationships to other genera, and detailed species lists. The book should be of interest to entomologists, taxonomists and systematists, especially in academic departments, natural history museum