Abstract
Anatomical changes of the brain and changes in the size of the motor neurones and neurosecretory III-cells were investigated in non-diapause and diapause individuals. The ultrastructure of the brain cells was also observed. The optic lobes developed in its size at the lateral sides of the brain hemispheres and the lateral ocelli of larva moved in and attached to the lateral surface of the optic lobes during the prepupal stage. One day after pupation, suboesophageal ganglion assumed a more anterior position, lying immediately ventral to the brain. These anatomical changes occurred in both non-diapause and diapause individuals. After the third day of pupation, neuropile of the optic lobes and motor neurones in the posterior and optic sides of the brain developed conspicuously in non-diapause pupa but not in diapause ones. Neurosecretory III-cell showed differnt changes in size from those of the motor neurones. Electron microscopic observation showed several types of glial cells, that is, perineurium cells with characteristic endoplasmic reticulum, two types of giant glial cells distinguished by their electron densities, and common glial cells filled with free ribosomes. Common neurones, motor neurones containing many mitochondria, and developing optic lobes were also described.
