Vogel's report of the production of glycerides rather than nectar as rewards gathered by bees described an association involving several genera of insects and numerous plant families. We report here that members of the Krameriaceae produce floral lips more unusual than those described by Vogel. Our data also provide evidence that the oils of Krameria are collected by bees of only one genus, Centris (Anthophoridae), and used, mixed with pollen, as larval food.