This gall is found quite frequently on Rubber rabbitbrush throughout western North America. In coloration and shape it resembles Russo's undescribed "spiny cone gall" (Rhopalomyia sp. A) but the scaly bracts covering the sides never recurve from the main gall body. The gall is always purple, with yellow tips to the bracts covering the surface. There is sometimes a white waxy substance covering parts of the surface. Some cross-sectioned galls have shown multiple larval cells at the base of a cavernous, hollow area in the upper half of the galls. <a href="https://www.inaturalist.org/observations/106265577">One dissected gall</a> had a single occupied larval chamber surrounded by green tissue.