THE ANTS, BEES, AND WASPS 



77 



with them, though they do not, so far as known, perform 

 any useful function. Their eggs are laid with the eggs of 

 the bumblebees, and the larvae feed on the food which the 

 bumblebees provide for their own young. Some of the guest- 

 bees resemble their hosts quite closely ; others are different 

 in appearance, so that it cannot be said in all cases that the 

 bumblebees are deceived by the resemblance. One effect of 



'- 



FIG. 46. Leaf-Cutter 

 Bee and Nest. 

 Natural size 



the dependence of 

 the guest -bees on 

 their hosts is seen 

 in the absence from 

 the hind legs of 

 the former of the 

 pollen-collecting 

 and pollen-carrying 

 organs, which have 

 probably been lost through disuse. It has been observed that 

 the bumblebees sometimes resent the introduction of one of 

 the guest-bees into their nest, though they may later become 

 accustomed to it and make no further trouble. 



Solitary Bees. There are solitary bees, just as there are 

 solitary wasps. Their habits are very diverse ; some make 

 nests of mud or dig tunnels in the ground ; some are car- 

 penters, boring into wood ; and others are leaf-cutters, taking 

 circular pieces out of leaves, which they use to line their 



