The primary type material of brachyceran Diptera (exclusive of Schizophora) housed in the Canadian National Collection of Insects and Arachnids, as of December 31, 1991 is catalogued. The collection contains 819 holotypes, 241 associated allotypes, 10 lectotypes, 4 associated allolectotypes, and 149 species that are represented by syntypes. Reference to the original description of each taxon is cited. Label data associated with the specimens are fully quoted. A bibliography and an index to named taxa are provided.

This is the first comprehensive synopsis of the biodiversity of Diptera, with chapters on all regional faunas, Diptera as ecological indicators, statistical techniques for estimating species diversity based on the known fauna, molecular tools and trends in digital publication.