MASON-BEES, 



31 



Nests., ffc. of 31 ason-Wasps.— About half tlie natural size.— 

 a The tower of the nest, b The entrance after the tower is re- 

 moved, c The cell, d The cell, with a roll of caterpillars pre- 

 pared for the larva. 



between them, giving it the appearance of fillagree 

 work. That it should be thus sHghtly built is not 

 surprising, for it is intended as a temporary structure 

 for protecting the insect while it is excavating its 

 hole; and as a pile of materials, well arranged and 

 ready at hand, for the completion of the interior 

 building, — in the same way that workmen make a 

 regular pile of bricks near the spot where they are 

 going to build. This seems, in fact, to be the main 

 design of the tower, which is taken down as expedi- 

 tiously as it had been reared. Reaumur thinks, that 

 by piling in the sand which has previously been dug 

 out, the wasp intends to guard its progeny for a time 

 from being exposed to the too violent heat of the 

 sun; and he has even sometimes seen that there were 

 not sufficient materials in the tower, in which case 

 the wasp had recourse to the rubbish she had thrown 



