The gall is found on stems, leaves, or inflorescences. This is a delicate, slender, 14–21 mm long gall, carried on a pedicel that is about half as long as the remainder of the gall (hence the species’ name). ... The gall is single-chambered, green to purplish-red, with longitudinal ridges, and tapered at both ends. The internal walls of the gall are smooth and shiny and the larva is usually found facing downwards at the bottom of the chamber. Galls are common and found from mid June to September. ... The structure of the gall is identical to that of R. fusiformae except for the presence of the pedicel.

...from a pedicel [sic] gall on Euthamia graminifolia

Galls are monothalamous and green to purple. The gall midge is apparently multivoltine and probably overwinters as an early instar in the plant crown. Host: E. graminifolia.