LIFE IN THE INSECT WORLD. 149 



cell. After working diligently for a little while 

 it walked off, and another took its place. Others 

 followed in succession, forming cells on each 

 side of the wall. 



More wax was soon needed, when some of 

 the wax-workers which had not yet removed 

 their scales, came and added materials to the 

 block, so as to enable the nurse bees to carry 

 on theirwork. 



Thus each one performed its part quietly and 

 harmoniously, coming at the moment when it 

 was needed, and doing what was required. 



But the cells were not yet finished, for wax 

 is not the only material employed in their for- 

 mation. If they were composed of wax alone, 

 they would be too tender and brittle to answer 

 the purpose of the bees ; arid they therefore 

 make use of a gummy substance called propo- 

 lis, to strengthen, cement, and varnish them. 



It appears that this substance is principally 

 obtained from the buds of the poplar tree. 

 While some are busily engaged, as we have 

 seen, within the hive, preparing the wax and 

 forming the cells, others fly away into the fields 

 and woods ; some in search of propolis, and 



