Emery, 1910b: 27 (diagnosis, catalogue); Wheeler, 1922: 750 (catalogue); Santschi, 1924b: 200 (all species key); Brown, 1975: 43 (diagnosis, review of genus); Baroni Urbani et al., 1992: 315 (phylogeny); Bolton, 1994: 14 (synopsis); Bolton, 1995a: 1038 (census); Bolton, 1995b: 58 (catalogue); Bolton, 2003: 37, 150 (diagnosis, synopsis); Brady & Ward, 2005: 593 (phylogeny); Brady et al., 2006: 18173 (phylogeny); Ward, 2007c: 555 (classification).