The purpose of this application, under Article 70.2 of the Code, is to conserve the current usage of the generic name Brachystoma Meigen, 1822 for a well-established genus of brachystomatid flies. The type species of Brachystoma has long been assumed to be Syrphus vesiculosus Fabricius, 1794, designated by Blanchard in 1840. However, the correct type species is Brachystoma longicornis Meigen, 1822, designated by Westwood in 1840, which is currently recognized as a valid species of Trichopeza Rondani, 1840. Acceptance of the earlier designation would threaten stability of nomenclature and taxonomy of the common and worldwide genus-group name Brachystoma Meigen, 1822 and make it the senior synonym of Trichopeza Rondani, 1840, thus requiring species in Brachystoma to be associated with the next available generic name Blepharoprocta Loew, 1862. To avoid the nomenclatural instability that would result from following the Principle of Priority, it is proposed that all type fixations for Brachystoma Meigen, 1822 prior to that of Syrphus vesiculosus Fabricius, 1794 by Blanchard (1840) be set aside.