MIGRATIONS OF BEES. 283 



quently, when the hive becomes too crowded for the 

 population, it is expedient to thin their numbers by 

 emigration. That a too crowded hive, however, is 

 not the only cause of emigration was proved from 

 several experiments by Reaumur. He frequently 

 possessed hives so full of bees that a portion of them 

 were compelled to remain on the outside, conglo- 

 merated in a mass, and yet no swarm was sent off to 

 thin their numbers. In other hives, on the contrary, 

 where there was much spare room, more than one 

 swarm was thrown off. To assure himself of this, 

 he placed a colony in a very large pyramidal hive, of 



Reaumur's large pyramidal hive. 



