SUMMARYDequeened swarms of honeybees were found to be attracted by other normal queens, by acetone extracts of normal queens, and by 9-oxodecenoic acid presented on a dead worker bee, but not by a living queen whose mandibular glands had been extirpated. When given the choice between their own queen and a normal queen from a colony in a hive, they always flew to their own queen.In small colonies whose queens were without mandibular glands, behaviour towards the queen was normal, including retinue behaviour. No queen cell cups were built; ovarial development in the workers did not increase.9-Oxodecenoic acid presented on a dead worker bee was attractive to caged bees and stimulated retinue behaviour in them; they showed inhibition of ovarial development.It is concluded that differences in the nature of the stimuli, together with differences in the motivation of the bees, are responsible for this divergent behaviour.