Aceria kraftella (Bitterbrush Stem Gall Mite)
The mite apparently emerges from stem galls in spring and infests new branch growth.
HOST: Purshia tridentata
RANGE: California, Nevada, Oregon, Idaho, Montana, and British Columbia.
”- Malcolm M. Furniss and William F. Barr: (1975) Insects affecting important native shrubs of the Northwestern United States©
Reference: https://www.biodiversitylibrary.org/page/46851717#page/69/mode/1up