MUTUAL AID AND COMMUNAL LIFE 433 



of each cell flat? How are those of the two opposite layers 

 of which the comb is composed related to each other ? 



Note several bees standing in the covered entrance to 

 the hive and steadily and rapidly vibrating their wings. 

 They are "ventilating" — ^that is, making currents of air 

 so that fresh air will constantly flow into the hive and foul 

 air out. Ventilating bees may also be seen scattered through 

 the hive. A movement of air through the comb is necessary 

 for the honey-making as well as for ventilation. The nec- 





Fig. 221. Honeybees building comb. (After Benton.) 



tar as it is gathered from flowers and poured out into cells 

 from the crops of the food-gathering bees is too watery to 

 be good honey, and must be partly evaporated. The venti- 

 lation assists largely in its evaporation. Touching the hand 

 to the glass sides note that the interior of the hive is warmer 

 on a cold day than the outer air. This is because the bees, 

 when necessary, buzz violently to make themselves unusually 

 warm and thus raise the temperature of the hive. When 

 young bees are being reared the hive must always be kept 



