Nest under bark of a fallen tree, open area along road (former burn) at 1350 m. Very fast. Keys out in Naumannn, et al. (1999) fairly well to Formica, possibly to F. ravida. Photos show important features: clypeal area, pronotal profile, hind tibia. Length 5 mm. Head very dark reddish brown, almost blackish; thoracic area and legs mostly brownish yellow; gastric area blackish.
Nest (see photo) in soil, just under the surface, partially under a rock, about 5 m from edge of Mission Creek. Adult identified with key of Naumann, et al. (1999). Features not evident in photos: tibial spur without comb, pedipalps 5-3, no dimorphic workers seen, length 5-6 mm.