...the much slower-developing summer-generation galls ... become apparent around mid June and vary considerably in size. These galls are composed of several wide leaves that surround dozens of densely packed, smaller and shorter leaves, giving the gall a shape of a little sunflower that appears flatter than the similar gall of R. solidaginis on S. altissima ... Occasionally, the outer leaves merge to form a continuous sheath around the central part of the gall. Summer galls reach their final size when the larvae are still tiny first instars that are found at the base of the rosette leaves. Six to twenty white, conical chambers, similar to those found in the spring galls, appear in the gall only when the larvae molt into third instars. Larvae are usually found deep at the bottom of the chamber, facing down. The chambers are 4–6 mm high and 1–2 mm wide, and are situated among the short leaves in the center of the gall rather than being individually surrounded by a group of longer leaves, as in the rosette gall of R. solidaginis.

- Netta Dorchin, Miles V. McEvoy, Todd A. Dowling, Warren G. Abrahamson, Joseph G. Moore: (2009) Revision of the goldenrod-galling Rhopalomyia species (Diptera: Cecidomyiidae) in North America^©