PROC. ENTOMOL. SOC. WASH. 80(3), 1978, pp. 397-402 MORNING GLORY BEES AND THE IPOMOEA PANDURATA COMPLEX (HYMENOPTERA: ANTHOPHORIDAE) Daniel F. Austin Abstract. — Oligolectic bees and their association with Tpomoea pandurata and its alHed species were studied in North America. Cemolobtis ipomoeae was found to be closely related to Ipomoea pandurata; Melitoma grisella has been shown to be linked with Ipomoea leptophylla; Ptilothrix sumichrasti was found with Ipomoea longifolia. The exact relationships between each bee species and each plant species are different. According to the literature three bee genera in the Anthophoridae, An-cijloscelis, Cemolobtis and Melitoma, are oligolectic to the genus Ipomoea (Michener in Muesebeck et al., 1951; Michener, 1954). Two of these, Cemo-lobus and Melitoma, occur in the eastern United States. Moreover, Robert-son (1929) suggested that these bees were probably associated with Ipomoea pandurata (L.) Meyer, one of the few endemic species of Ipomoea in the eastern United States. My study began in the summer of 1971 largely as an attempt to confirm the existence of close relationships between these bees and plants. Once oligolecty' was documented, the fol-lowing two summers were used for field study of widely separated popula-tions of /. pandurata. Patterns of insect behavior at the flowers were found to be essentially constant throughout the range of bees and plants. Materials and Methods Field studies were made in Florida, Georgia, South Carolina, North Carolina, Virginia, Pennsylvania, Ohio, Indiana, West Virginia, Illinois, Missouri, Kentucky and Tennessee. In addition to the field studies, her-barium material of Ipomoea has been examined in A, FAU, FLAS, GH, UNC, US, MO, and USE (abbreviations follow Lanjouw and Stafleu, 1959). The herbarium and field studies were augmented with various floras to provide accurate distributions (Britton & Brown, 1898; Small, 1903, 1933; Wooten & Standley, 1915; Deam, 1940; Tidestrom & Kittell, 1941; Fernald, 1950; Kearney & Peebles, 1951, 1961; Jones et al., 1955; Mohlenbrock & Voight, 1959; Gleason & Cronquist, 1963; Steyermark, 1963; Justice & Bell, 1968; Radford et al., 1968; Conard, 1969; Correll & Johnston, 1970; Wharton & Barbour, 1971; Brown, 1972; Ehis & Chester, 1973). Insects were deter-mined with the help of Paul D. Hurd, Jr., and several other members of the Entomology Department, Smithsonian Institution as well as Mitchell (1960, 1962).