Last year a short note (Musgrave, 1949) described the possibilities of fluorescein for marking insects. The method has since been adopted and much elaborated by the Apiculture Department here (Townsend, 1950).

But another and very interesting question remained insufficiently answered: was it possible to dust a growing crop with fluorescein (and presumably, certain other solids) in such a way that visiting bees alighting on the crop would pick up the dust and carry it back to the hive an their bodies in detectable quantities? If it were then a very useful tool in field research in Entomology generally might well be available. During the summer of 1950 an experiment was devised to answer this question.