Camponotus (Carpenter Ants) of different species.
Left & right: Camponotus on the Wooly-fruited Lomatium. [p 23]

Smooth back -- even though there is structure between the thorax & gaster. I saw this ant on the same plant as the Formica ant foraging, in the previous image -- 4 minutes before that one. I followed each ant for 4-5 minutes. This one looks like a Camponotus -- confirmed by Merav Vonshak. The "foraging ant" is clearly a Formica.