Cincticornia simpla

The oval blister galls on oak produced by this species are so insignificant as rarely to attract the attention of any but those specially interested in the study of insect galls. This species was reared in small numbers from several lots of galls taken on Quercus velutina in MA and also from blister swellings on the leaves of red oak, Quercus rubra, taken in the vicinity of Albany NY.

Gall. An irregularly oval pustulate swelling 5 to 6 mm in diameter and showing equally on both surfaces but with no distinct nipple. The galls are a variable brown in the fall, darker than the normal tissue and occur here and there on the leaf. Apparently the same species produces a slightly green or variable yellowish and red elevation on both surfaces of the leaf some 5 by 7 mm in diameter. Several larvae occur in the cavity beneath.

- EP Felt: (1915) 31st Report of the State Entomologist on Injurious and Other Insects of the State of New York^©

Reference: https://www.biodiversitylibrary.org/page/36619989#page/545/mode/1up