Robber flies inhabit all regions of the world except the arctic regions. The highest diversity is in the subtropical and tropical regions, but our knowledge of these fauna is insufficient and the number of new described species increases rapidly. It seems to be that robber flies prefer open areas. In some deserts they are amongst the dominant predators. Our impression of the distribution is dependent on the knowledge of species. A first assumption is possible on the subfamily level. For example: The Leptogastrinae are distributed world-wide, whereas the Ommatiinae are concentrated in the Oriental, Afrotropical and Australian regions - the Stichopogoninae in the Palaearctic region - and the Apocleinae in the Neotropics.