Puyallup/Puyallup River, upstream from Meridian Bridge, Pierce County, Washington, USA June 5, 2018
My guess is Bombus melanopygus from this site and the Forestry Bumble Bees of the West site. But I'm still not very sure in my ID's. The plant is Coastal Manroot, Marah oregana. As always, keep or frass at your discretion.