Fig. 7. Tracings of LTKLI neurons in the brain of a fifth instar larva of M. sexta. (A) Cell bodies of the brain (filled cell bodies are posterior, unfilled anterior). DN, cell body of the large descending neuron. (B) Tracing of cell bodies and processes of some of the major posterior LTKLI neurons. Note the varicose fibres distributed in the brain neuropil and in the four commissures connecting the hemispheres. The arrow indicates two of the ascending axons derived from the ventral nerve cord, with arborizations in the tritocerebrum and protocerebrum. DN, the large descending neuron with processes in the protocerebrum and axon (also at arrow) to the ventral nerve cord. Scale bar, 100 µm.