Neurosecretion in the Brain of the Larva of the Sheep

Six groups of neurosecretory cells were identified in the brain of the mature larva of Lucilia caesar. Five of these groups belonged to the category of medial neurosecretory cells and one to that of lateral neurosecretory cells. The groups differ in position, cell size, staining characteristics, and sequence of activity. It is apparent that only some of the groups are concerned with the process of thoracic gland activation, though all function during metamorphosis. At least one group, not concerned in thoracic gland activation in the non-diapause larva, is continually active during diapause.