MUTUAL AID AND COMMUNAL LIFE 431 



board, which can be simply lifted off whenever it is desired 

 to see what is going on at the entrance. Here can be 

 seen the "ventilating," the alertness of the sentinels and 

 guards, the killing of drones, the constant arrival of pollen- 

 laden food-gatherers, etc. 



But observations may well begin in the field. Note the 

 gathering of flower pollen (fig. 220). Where does the bee 

 put the pollen as it collects it? Why doesn't the pollen 

 fall off? Kill a bee in a killing-bottle and examine care- 



FiG. 219. An "observation" beehive with glass top and sides. (Drawn 

 from hive in the author's laboratory.) 



fully one of its hind legs. Make a drawing showing the 

 pollen basket. At the flowers 'some of the bees do not 

 collect pollen but nectar. Examine the complex "tongue" 

 of a dead bee. By means of this tongue nectar is sucked 

 or lapped up and swallowed into a crop, where it is not 

 digested but retained until the bee returns to the hive. 

 By observing the bees there and examining the comb-cells 

 find out what is done with the pollen and nectar collected 

 by the food-gatherers. 



