Contents

14 January 1972
Vol 175, Issue 4018

About The Cover

Bumblebees regulate their thoracic temperature when foraging for nectar. At ambient temperatures below 24° the thoracic temperatures is maintained at 32° to 33° at ambient temperatures above 24° the thoracic temperature rises. See page 185. [Photo courtesy of U.S. Department of Agriculture, Washington, D.C.]