D. (Callirhytis) clarkei [the D is a typo as this is described in the section of the paper regarding Bassett's Andricus subgen Callirhytis).

Small, black polythalamous galls. The sterile flowers of Q. ilicifolia transformed into galls in such countless numbers as to make the aments look like elongated blackberries. The largest gall I have found measured .11 of an inch in diameter and contained four larval cavities. Most of them are considerably smaller, having from one
to three cavities, and measuring from .05 to .08 inch.

Small as these galls are, and short and early as their season is, at least two-thirds of them contain at this writing (November, 1889) living parasitic larvse. In most cases nearly every flower has been transformed into a gall, though in a few the galls are sparingly intermixed with the flowers.

At the time the galls were received, early last spring, no flies had made their appearance, but they came out in considerable numbers during the month of May. They are all females, and are described as follows.

- HF Bassett: (1890) New Species of North American Cynipidae (1890)^©

Reference: https://www.biodiversitylibrary.org/page/7490909