1. The site for regulation of heart rate is the pterothoracic ganglia.
2. Heart rate increases when the animal goes from an inactive to an active state. At low air temperatures the transition is from torpor to warm-up and above 35°C the transition is from torpor directly to flight.
3. The heart of Cecropia moths isolated from neural connexions to the thoracic ganglia responds directly to temperature changes.
4. In actively flying animals the heart rate increases in response to thoracic heating.