246 TRANSFORMATIONS OF INSECTS. 
appears to keep a sharp look out for them, and takes care to 
spare itself all the trouble possible by repairing the broken down 
cells and making them as good as new. The female cleans out 
the inside, removes the débris of the cocoons, and brushes out 
the skins of the larvae and nymphs, and all uncleanly matters. 
Then the holes are repaired, the openings are closed up, and the 
old nest begins to resemble one of the year. Sometimes the 
mason bee becomes lazy, and then she penetrates into the nest 
fi 
THE Osmia aurulenta AND ITS NEST. 
which some other one is making, and, if she likes the position, 
endeavours to maintain it by force. Réaumur says that when one 
of these bees was gone to collect some cement wherewith to finish 
up the cell, M. du Hamel saw another one enter in without any 
ceremony, crawl all about, and turn everything over, just as if 
the nest belonged to it. That this was not done out of curiosity 
was gleaned from the fact that when the true mistress of the 
nest arrived, laden with building materials, the other one would 
not allow her to enter, and she was obliged to fight the usurping 
