ID'd by @colinpurrington via Twitter. Reference article: https://thedragonflywoman.com/2011/06/27/mites/
"Hairy-footed pollen mites"? so thick on thorax of Osmia mason bees that they couldn't fly. (My fault for leaving same tubes up for years). Two years later we have no mason bee activity even with 3 new houses & tubes up.
Cochrane District, ON
These don't have the yellow on the legs that I think all of our Hylaeus have here in ON...
Sharing a Texas Pricklypoppy flower with a Texas Flower Scarab