This species forms galls similar to those of R. hirtibulla except that they are not covered by long trichomes.

This small monothalamous gall (Fig. 13) is similar in size and structure to that of R. hirtibulla. The grayish surface of the mature gall is clothed with trichomes the same as on the leaf. The galls occur singly or in large clusters both on the persistent leaf series and stems of the previous year's growth. Adult emergence holes are similar to those of R. hirtibulla (Fig. 12). The galls have been found on only one small plant at the type locality.

- Robert G. Jones, Raymond J. Gagné, William F. Barr: (1983) Biology and taxonomy of the Rhopalomyia Gall Midges (Diptera: Cecidomyiidae) of Artemisia tridentata Nuttall (Compositae) in Idaho^©