Communication in social insects to a very considerable extent is mediatedby the action of chemical messenger molecules or pheromones. These areproduced in an impressive variety of exocrine glands, that occur all over thebody of these insects. Various gland types as well as various types of pheromonal communication can be distinguished. This article gives an example of each of the 5 anatomical types, representing the 5 major social insect groups, illustrating their structural diversity and their involvement in several pheromonal functions.