Galls found on the upper half of the stems of H. divaricatus, appearing like swellings of the stem; symmetrical, varying from ovate to spindle form; the long diameter of the gall in the axis of the stem of the plant; color the same as the stem. Walls of the gall are woody, hard, and about 1mm thick. The interior is filled with a soft, pith-like substance through which the larvae tunnel and on which they feed. Each gall contains 1 to 10 larvae.

- William Brodie: (1894) Canadian galls and their occupants^©

Reference: https://www.biodiversitylibrary.org/page/39457465