A new species of a new subgenus and a similar known species referred to the genus Flagellisargus J Zhang, 2012 are described and illustrated based on a male and a female impression fossils of these flies: Flagellisargus (Changbingisargus) parvus subgen. et sp. n. and Flagellisargus (Flagellisargus) cf. sinicus J Zhang, 2012. The latter taxon is the first record of a female Flagellisargus. Recently taken out of Archisargoidea, this study concludes that Flagellisargus should be an archisargid genus based on the known (male) and new (female) impression fossils. The placement of Daohugosargus J Zhang, 2012b is reassessed. It demonstrates close similarities in body structure and wing venation to archisargid flies, and can be retained as an archisargid genus. Archirhagio mostovskii J Zhang, 2015 is separated from Archirhagio zhangi K Zhang et al., 2009. Helempis Ren, 1998 could be, as a separate genus, placed in Archisarginae, Archisargidae.