They are characterised by: Stigma present, pygidial plate present (except in Ammobatoidini) and often modified with strong,
blunt spines or bristles or modified to slender bifid or simple pointed apex; arolia is present;
episternal groove does not extend below scrobal groove except in the tribe Caenoprosopidini; two or three submarginal cells.Source: Michener (2007). Bees of the World. John Hopkins University Press
