Galls were collected in Hood River County, Oregon on Sept. 3, 2023 from Doellingeria ledophylla by Jeff Ward, who states: "Adult midges emerged on 2023/09/04 and were preserved in 95% ethanol. These were sent to Dr. Raymond Gagné who identified them as an undescribed species in genus Rhopalomyia. The specimens are now in the USNM collection."

A key difference between this and Unknown d-breweri-leafy-rosette-gall, which occurs in California on a host plant in the same genus, is that this had many tiny larval chambers instead of a single comparatively large chamber.