BEES AND WASPS AS MINERS. 



65 



nected with the main shaft by short passages. The 

 sides of the shaft are rough, but varnished over with a 

 mucuslike secretion. After building these chambers 



Eose-leaf bee. 



the Andrena gathers balls of pollen and puts one in 

 each chamber with an egg, which hatches out a grub 

 that lives on the pollen until it is ready to make its 



