1929] 
Biology of Mining Bees 
163 
from the walls in the process of biting out the hard clay, or 
the scraps that dropped while she fashioned her thimble- 
like cups. 
Unlike the homes of some species, this gallery was roomy 
enough that the owner could turn around in it, for while 
she always backed out when she emerged with her load of 
mud, she did just the opposite when she came out for water, 
for then she always came out head first and dashed away. 
One singular feature occurred in the great majority of 
individuals observed ; when they had used up the water, and 
had applied the last load of mud to the turret, they did not 
realize their need and fly directly out and away for more 
water, but re-entered the hole as usual, sometimes stayed 
in a few minutes and then came out head-first and flew 
away to the watering place. This might be due to the fact 
that the bee did not know that the water was gone and 
must have as a stimulus the experience of biting out the 
dry soil to arouse her inclination to go for more water. On 
the other hand, it might be that she entered the hole only 
to turn around so as to leave head-first, instead of tumbling 
out backwards as when she had applied her mud. The bees, 
w T hen they had arrived at the water, did not alight upon the 
surface as do certain wasps, by spreading their legs, but 
landed on the soft mud on the margin, and with the long 
tongue protruding lapped it up. They were not bound by 
instinct even to go to the same place regularly for water, for 
one year after a rain many were seen availing themselves 
promptly of the temporary convenience and gathering the 
drops from the vegetation very near to their doors, instead 
of going to their customary place. 
The round trip for water consumed from one-fourth to 
one-half minute, and the number of pellets of mud that 
could be carried out with each mouthful of water was inter- 
estingly varied. One bee which was watched for one hour, 
from 2:03 to 3:05 p.m. made twelve trips for water, and 
removed forty-seven balls of mud. When one considers that 
the mud was not only excavated, but was built into the 
chimney, one feels that this is a good hour’s work for so 
small a creature. One gulletfull of water would remove 2 
to 5 balls of earth, the greatest frequency being 4 ; this num- 
