1. Abrams J., Eickwort G.C., 1980.—Biology of the communal sweat beeAgapostemon virescens (Hymenoptera: Halictidæ) in New York State.Search (Cornell Univ. Agr. Exp. Sta.), 1, 20.
2. Batra S.W.T., 1966.—The life cycle and behavior of the primitively social bee,Lasioglossum zephyrum (Halictidæ).Kans. Univ. Sci. Bull., 46, 359–422.
3. Brothers D.J., 1972.—Biology and immature stages ofPseudomethoca f. frigida, with notes on other species (Hymenoptera: Mutillidæ).Kans. Univ. Sci. Bull., 50, 1–38.
4. Claude-Joseph F., 1926.—Recherches biologiques sur les Hyménoptères du Chili (Mellifères).Ann. Sci. nat. (Zool.), 9, 113–268.
5. Eickwort G.C., 1969.—Tribal positions of Western Hemisphere green sweat bees, with comments on their nest architecture (Hymenoptera: Halictidæ).Ann. ent. Soc. Am., 62, 652–660. 1975.—Gregarious nesting of the mason beeHoplitis anthocopoides and the evolution of parasitism and sociality among megachilid bees.Evolution, Lancaster, Pa., 29, 142–150.