F. vesca or F. virginiana?
A swarm of dozens of black bumble bees on a dead snag.
Not sure what they were doing...some kind of battle? Every time a bee tried to enter the snag (nest?), another would prevent it.
Lovely yellow pea flower with a dark orange obverse side.
Or is this just a strangely marked M. guttatus?
Hundreds of these on the trail from Yosemite Falls in the evening. None interacting, though. Wonder what they were doing?