Structures of Halictinae. a, b, Labrum of Pseudaugochlora graminea (Fabricius) female, showing dorsal keel of apical process and greatly thickened basal area of labrum; c, d, Labrum of male of P. graminea, showing lack of keel on apical process; e, f, Labrum of female and of male of Corynura chilensis (Spinola); g, h, Labrum of female and of male of Augochloropsis metallica (Fabricius); i, Labrum of female of Temnosoma smaragdinum Smith, a cleptoparasite whose female lacks a keel on the apical process. j, Apex of metasoma of female Halictus rubicundus (Christ), showing median specialized area of T5; k, T5 of female of Pseudaugochlora graminea (Fabricius), showing slit in median specialized area. l, m, Dorsal and ventral views of male genitalia of Corynura chilensis (Spinola); n, S7 and S8 of same, fused; o, p, S7 and S8 of same, artificially separated. From Eickwort, 1969b, except j and k, which are modified from Michener, McGinley, and Danforth, 1994. (source: Michener, 2007)