We believe these tiny (4-6mm long) beetles are Scelolyperus schwarzii. The penstemon gives you a good idea of their size. The two that are in full view are likely males, as males have a prominent arch on each hindleg. According to the Pacific Northwest Insects book, this beetle “Feeds on leaves of many different woody shrubs, such as roses, blackberries, and Oregon Grape. The author didn’t specify whether this applies for both larvae and adults …but it looks like this group is enjoying some parts of the flowers. These beetles range from British Columbia to California east to Montana and Wyoming. Look for the adults from May to September. 

Photo by: Kelly Dix on 5/29/21 near Hamilton, MT