THE CORRELATION BETWEEN THE RHYTHMS OF DEVELOPMENT OF CORPORA-ALATA AND THESE OF DEFINITIVE STRUCTURES IN THE ONTOGENY OF HEMIMETABOLIC INSECTS

The correlation between the rhythms of development of corpora alata (an endocrine organ secreting the juvenile hormone) and these of definitive structures was studied in a typical hemimetabolic insect Eurygaster integriceps Puton (Hemiptera). The number of cells in corpora alata remains during the first and second larval stages at the same level as in embryos. Synthetic power of these endocrine organs begins to increase with the beginning of development of the imaginal structures, and the maximum increase in the number of cells takes place during the last two larval stages. The terms of the increase of the synthetic power of corpora alata are compared to the development of imaginal structures and to ontogenetic increase of larval weight. The results are discussed in the light of current concepts of evolution of ontogenesis in insects.