The dance flies or Empididae are one of the largest groups in Brachycera (Diptera), and belong to the superfamily Empidoidea. Now 179 genera and 4969 species are known from the world. They can be easily identified by the small rounded head and humpbacked thorax (Plates I-II). The agults and larvae are predacious, including some important predators of some pest insects such as aphises, psyllids, whiteflies, coccids, mosquitos, flies and mites, except for adults of some species being flower visitors.
In the present book, the world catalog of Empididae is complied. Fossil taxa are excluded, as all of the fossil Diptera were cataloged by Evenhuis (1994). The morphology of adults is outlined. Now the family Empididae is classifided into 15 subfamilies with definition of each subfamily, of which Homalocneminae is recgonised as a valid subfamily and Brochellinae is described as a new subfamily. A cladistic analysis of phylogenetic relationships among subfamilies of Empididae is presented. The monophyly of Empididae is confirmed.