It has been known already for a long time that cell death during em- bryonic development is a normal aspect of morphogenesis and differ- entiation (for review, see GLÜCKSMANN, 1951; SAUNDERS, 1966). Cell death also plays a role in the destruction of larval organs of holo- metabolous insects. However, in these animals cell death also occurs in developing tissues such as the imaginal disks. These disks are very suitable for the investigation of the relation between cell death and morphogenesis, since they have a relatively simple structure. More- over, there are numerous mutants of Drosophila characterized by abnormal adult structures, from which this relation can be studied. Recently this was done by FRISTROM (1968, 1969). She reports the occurrence of cell death in the imaginal disks of the wild type and of some eye and wing mutants of Drosophila melanogaster. In the wild type cell death is found only in the eye disk. In the disks of the mutants cell death could be correlated with the missing parts of the corresponding adult organ (cf. GOLDSCHMIDT, 1935)