Certain species of genus Lebia (Carabidae) are strikingly similar in color to species of flea-beetles (Alticinae, Chrysomelidae) with which they are regularly associated on the foodplants of the latter. A host-parasite relationship is suggested. Other chrysomelids, known as hosts of a Lebia, are not imitated. It is proposed that the jumping habit of the flea-beetles is an effective protection against certain birds and that they are imitated by the accompanying Lebia for this reason. The situation is interpreted as a case of Bates'ian mimicry. A similar case is the striking resemblance between two species of the African genus Lebistina and their respective host, flea-beetles of the genus Diamphidia. These are used by the bushmen for the production of arrow-poison. It is therefore assumed that here the protection is of a chemical nature.