Heteroecus fragilis
Detachable, monothalamous stem gall with a thick wall formed from many small, fragile, sponge-like chambers. Yellow, spherical, 5-8 mm in diameter.
(Fig. 4)
Host:
Quercus palmeri (syn. Quercus dunnii)
- D C Dailey, C M Sprenger: (1983) Gall-inducing cynipid wasps from Quercus dunnii Kellogg (Hymenoptera)©
Reference: https://www.biodiversitylibrary.org/page/56199180#page/53/mode/1up