152 evolution: the ages and tomorrow 



packs pollen tightly into pollen cells and removes dirt and 

 debris from the cells and hive in general and carries it out- 

 side. With wax glands now fully developed she carries on 

 a marvelously controlled building and repair activity, math- 

 ematically precise and architecturally perfect. She knows 

 how to build special cells for the queen and drone; and even 

 though there are many workers milling about in any one 

 corner of the construction, everything fits in perfectly. 

 Gradually desisting from this work, she stands guard at the 

 door of the hive for a couple of days. 



And now comes the great moment. The nearly three- 

 weeks-old worker becomes restless and begins to take short 

 flights into the open country, farther and farther each time, 

 storing up a photographic memory and navigating by the 

 sun with the sure genius of a high-level instinct. She be- 

 comes exclusively a food gatherer, bringing back nectar and 

 pollen and delivering it up to her younger workers. Two 

 weeks and a little more of this and she is very old. Her flights 

 become shorter and more infrequent, she sits about the hive 

 a great deal; and finally she dies in the sixth week of her 

 winged age. Her corpse is transported out of the hive by 

 her sister workers and thrown away. 



Von Frisch has given us a new insight into the degree of 

 development of the sense organs of the bee and of the per- 

 ceptual organization as a whole. The big compound eyes 

 are very eflicient organs of sight, being so rounded and well 

 placed on the head that the bee can see above, below, front, 

 and back at one and the same time. Built into these eyes is a 

 device which permits the bee to determine the direction in 

 which the light of the sky is polarized, and with this device 

 the bee can tell the direction of the sun even when it is not 

 directly visible. (Seen directly, sunlight vibrates transversely 

 in all directions to the same extent. When scattered by at- 

 mospheric particles, the light of the sky vibrates more in 

 one direction than another. Man determines this by a prism 

 device.) The bee's eyes see color somewhat differently than 



