opacithorax. Eciton (Acamatus) californicum subsp. opacithorax Emery, 1894c: 184 (diagnosis in key) (w.) U.S.A. Wheeler, W.M. & Long, 1901: 163, 173 (m.q., respectively); Wheeler, G.C. & Wheeler, J. 1984: 273 (l.). Combination in E. (Neivamyrmex): Smith, M.R. 1942c: 555; in Neivamyrmex: Borgmeier, 1953: 5. Raised to species: Emery, 1900a: 186. Senior synonym of castaneum: Borgmeier, 1955: 502. See also: Smith, D.R. 1979: 1332; Wheeler, G.C. & Wheeler, J. 1990a: 461; Snelling, G.C. & Snelling, 2007: 487.