All: outdated key to species (in German) on page 65 of Paramonov, 1929: “Beiträge zur Monographie einiger Bombyliiden-Gattungen. (Diptera)." Contact me
Africa (southern): key to species in Greathead, 2006: “New records of Namibian Bombyliidae (Diptera), with notes on some genera and descriptions of new species." Link