Honeybee nurses (8 days old) were injected with C-14-phenylalanine. These bees then dispensed the C-14-labelled protein-rich products of their hypopharyngeal glands to the queen and the brood, and also to young drones and workers of all age classes. In small colonies containing 400-800 bees, nearly one-quarter of the radioactivity which could not be recovered in the nurses was fed by them in a protein-bound form to other members of the worker caste. During one night, one nurse fed an average of 4-5 foragers with proteinaceous food. The role of nurses in the work allotment system of honeybee colonies therefore needs a new, extended definition. Nurses are largely responsible for preparing nutrients from pollen, which is difficult to digest. They then distribute the nutritionally valuable protein produced by their hypopharyngeal glands to practically all hive mates.