Megodon was proposed for a species from Madagascar with an unusual scutellum.
Megodon stuckenbergi Keiser, 1971.
Keiser, F. (1971) Syrphidae von Madagaskar (Dipt.). Verhandlungen der Naturforschenden Gesellschaft in Basel 81, 223-318.
See original description as a attached file (in German).
Species only known from Madagascar.