Callirhytis quercusagrifoliae
(Andricus quercusagrifoliae)
Tiny, 2 mm long, one-celled blister galls develop on leaves, in aborted buds, and on petioles. These galls develop rapidly, and bisexual males and females emerge in April, seven to eight weeks after egg deposition.
”- Russo, Ronald A. : (2021) Plant Galls of the Western United States©