1. Tonic discharges of homologous units in the left and right metathoracic leg nerves in response to increases and decreases in light intensity were observed.

2. Periodic variations in the frequencies of these units was shown to be related to leg movement and at a frequency appropriate for walking.

3. The intensity and duration of discharge of these units was related to the change in light intensity and the frequency of stimulation.

4. The unit of one side normally fired at a higher frequency than that of the other.

5. This was separate from the asymmetry produced by placing the animal in a rotating drum with a single 55° stripe. In this case, clockwise movement of the stripe produced a higher frequency discharge on the left side, while a counterclockwise movement reversed the frequency ratio.

6. Units in the connectives appeared to trigger this discharge.