Ultrastructural study of the postembryonic development of the neural lamella of Galleria mellonella L. (Lepidoptera).

The neural lamella encapsulating the brain of the wax moth Galleria mellonella develops from a very thin (80-120 nm) layer in the first larval instar, resembling the basal lamina, to a thick (1-4 micrometer) sheath composed of two zones in the seventh (last) instar. After its breakdown at the time of larval-pupal ecdysis the neural lamella is reconstructed in the pupa, 2-3 days before pupal-adult ecdysis. The cells of the perineurium seem to be responsible for the formation of the neural lamella, both in the larva and pupa, even though its ultrastructure differs at these stages.