191 p. : ill. (some col.) ; 26 cm.Includes bibliographical references (p. 165-172)."Previous classifications and phylogenetic trees of the Asiloidea and the Bombyliidae are reviewed. Data from male genital musculature presented by Ovchinnikova (1989) and female genitalia by Muhlenberg (1971b) are reanalyzed within a numerical cladistic framework. A cladogram of the Bombyliidae and their relatives is constructed based on a data matrix containing 87 taxa and 154 characters. This study includes 24 non-Bombyliidae taxa used as outgroups, from the families Rhagionidae, Nemestrinidae, Acroceridae, Asilidae, Therevidae, Apioceridae, Mydidae, Scenopinidae, Hilarimorphidae, and Apsilocephalidae. I chose 63 ingroup species representing all the currently accepted subfamilies and tribes except the Xenoprosopinae and Villoestrini. 147 of the characters used were derived from adult morphology and 7 were from larval morphology. The data set was analyzed using the parsimony program Hennig86 which identified 8 most parsimonious trees, each with a length of 716 steps, consistency index of 0.25, and retention index of 0.71. All characters are described and almost all are illustrated using line drawings, photographs, and scanning electron micrographs. Previously used characters are reanalyzed and new character systems are introduced, especially features of the postcranium and cibarium. The Acroceridae and Nemestrinidae do not form a monophyletic group and each should be recognized at superfamily level. The Asiloidea is also weakly monophyletic, based largely on larval features. The Apioceridae is found not to be monophyletic, some included genera being more closely related to the Mydidae. The Hilarimorphidae, including the proratine Apystomyia Melander, form the sister-group to the Bombyliidae. The remaining Proratinae form a clade with the Scenopinidae, confirming recent work on the subfamily. Bombyliidae, as here defined to exclude genera traditionally placed in the Proratinae, is found to be monophyletic, however the evidence for its monophyly is weak. The subfamily Heterotropinae was found to be nested within the Bombyliidae, thus the free-living, predatory habits of Heterotropus Loew larvae are interpreted as reversals from a parasitoid lifestyle rather than a primary plesiomorphic condition. In a reclassification of the Bombyliidae, 15 subfamilies are recognized: the Mythicomyiinae, Oligodraninae, Usiinae, Toxophorinae, Lordotinae new subfamily, Heterotropinae, Bombyliinae, Crocidiinae new statues, Mariobezziinae, Oniromyiinae, Cythereinae, Lomatiinae, Anthracinae, Tomomyzinae, and Antoniinae. The position of Sericosoma Macquart requires further research; it exhibits closest affinity with the Mariobezziinae. The proposed classification is conservative and reflects much of the structure of previous classifications. Chief differences include the recognition of the Gerontini and Systropodini as tribes of the Toxophorinae rather than separate subfamilies and the synonomy of the Cylleniinae within the Cythereinae. Crocidiinae is recognized as a subfamily, rather than a tribe of the Bombyliinae. Lordotinae is the only new family-level taxon proposed, characterized by the highly modified, telescoping female genitalia which are adapted for inserting the eggs into the substrate. Tribal divisions within the Bombyliinae, Lomatiinae, and Anthracinae are discussed. A key to the subfamilies of Bombyliidae is presented, and all subfamilies are diagnosed, synapomorphies listed, and their taxonomic scope, distribution, and biogeography briefly discussed. The fossil history of the Bombyliidae is discussed in relation to the cladogram. Bombyliidae probably originated in the Jurassic and had undergone much diversification at subfamily level by the end of the Cretaceous. The evolution of the bombyliid postcranium and female sand chamber is discussed in light of the cladogram. The evolution of the acanthophorites within the Bombyliidae is discussed in relation to the occurrence of this feature in other families of Asiloidea"--P. 5