xanthochroa. Liometopum xanthochroum Roger, 1863a: 167 (q.) MEXICO. Mayr, 1866a: 497 (w.); Emery, 1896c: 2 (w.); Wheeler, W.M. 1942: 247 (l.); Wheeler, G.C. & Wheeler, J. 1951: 193 (l.). Combination in Azteca: Forel, 1878: 384. Junior synonym of instabilis: Mayr, 1878: 870. Revived from synonymy as subspecies of instabilis: Emery, 1893b: 137. Revived status as species: Emery, 1896c: 2. Senior synonym of costaricensis: Longino, 1992: 1594. See also: Longino, 2007: 52.