SUMMARY

1. Abdominal nerves of Rhodnius prolixus were studied with the light microscope under high-power Nomarski optics with a minimum of surgical interference. The preparation was perfused with bathing solutions which could be changed during time-lapse cinematography. 2. The structure of the nerve trunks was studied by light and electron microscopy. 3. The movements of intracellular organelles are described and discussed. 4. Saltatory movements of organelles, probably mitochondria, were followed at different temperatures. Rate of saltation varied linearly with temperature. 5. Axonal flow (bulk movement of cytoplasm) did not occur in healthy abdominal nerves