Thank you for your report! This is the Banded alder borer, Rosalia funebris. They are not pests. Their grubs live in dead branches of red alder and some other forest trees. One of our most attractive and distinctive native longhorn beetles, they seem to be having a very "good year" as we are getting many reports this summer.

Tom Valente
Aug. 1, 2025, 3:03 a.m.