An oval, thin-walled, pubescent cell, length about 1 mm, attached to underside of leaf and at an oblique or nearly vertical angle. Gall grayish on A. heterophylla (=A. douglasiana) to nearly black on A. tridentata. Galls on flower buds similar but thinner walled.

- EP Felt: (1916) New Western Gall Midges^©

Reference: https://www.biodiversitylibrary.org/page/8184701