Formica sessilis Say, 1836: 287 (w.q.) U.S.A. (Indiana). Nearctic.

Primary type information: Primary type material: neotype worker (by designation of Hamm, 2010: 24). Primary type locality: neotype U.S.A.: Indiana, Posey County, New Harmony, 38.130°N, 87.935°W, 110 m., 21.vi.2009 (“5 m. from the grave of T. Say”) (C.A. Hamm). Primary type depository: MCZC (neotype). Type notes: Original type data: syntype workers, queens (numbers not stated), U.S.A.: Indiana (no further data) (T. Say), depository unknown (no material known to exist).