Taxonomic revision of Romaleosyrphus Bigot (Diptera, Syrphidae), including descriptions of seven new species.

The genus Romaleosyrphus Bigot is reviewed, including the description of seven new species (R. argosi Moran, sp. nov., R. bigoti Moran, sp. nov., R. drysus Moran, sp. nov., R. nephelaeus Moran & Thompson, sp. nov., R. soletluna Moran & Thompson, sp. nov., R. vockerothi Moran & Thompson, sp. nov. and R. woodi Moran, sp. nov.). Romaleosyrphus arctophiloides (Giglio-Tos), comb. nov. is transferred to Romaleosyrphus. Romaleosyrphus stat. rev. is redefined to represent the monophyletic unit of species within Criorhinina which possess holoptic males, a proximal ventral half of vein C with setae, a broad intersection of vein R1 with vein C, the distal part of R4+5 beyond M1 longer than cross-vein h and appressed pile on the abdomen. Descriptions, habitus and genitalia photographs, distributions, and an illustrated key for all nine Romaleosyrphus are presented. DNA barcode data are provided for eight of the species with a cytochrome c oxidase subunit I gene tree presented and discussed. [ABSTRACT FROM AUTHOR]