I do not recognize any subspecies of Syrphus balteatus. The taxon Syrphus balteatus formosae Sack, 1913, described from Taiwan, is not a subspecies of the present species, but is a synonym of Episyrphus viridaureus, as shown by Ghorpade 2009. The status of Episyrphus viridaureus is controversial, because this Asian and Australian species is morphologically very variable and some authors accept the many named "forms" as good subspecies or species. However, Ghorpade (2009) has argued that all named forms are infrasubspecific and has synonymized them with Episyrphus viridaureus. This notion is strongly supported by rearing experiments by Wright and Skevington (2013), who were able to show that different color variants in Episyrphus viridaureus can be produced by simply changing the temperature during development.