THE OSMLE. 245 



provisions,- and "dosed perfectly, but yet the labour is not over, 

 for the bee builds up a sort of roof or general covering to the 

 whole, and uses larger sand grains than those which enter into 

 the composition of the cells, and thus the external walls ^of-^ the 

 nests are found to have great thickness and wonderful hardness/ 

 The larvse will have plenty to live upon, and certainly every care 

 has been taken to place them out of danger. When they are full 

 o-rown they add to their imprisonment by making a cocoon of a 

 paper-like tissue, which looks as if it were varnished. Their 

 metamorphosis is completed within, and the adult insects fly. 

 But how do they manage to get out of their strong and prison- 



A NEST OF Chalicodoma viuraria DETACHED AND SEEN FROM WITHIN. 



like home } Do they contrive to pierce the cement, which is as 

 hard as stone, and Avhich resists the blow of a hammer ? Every 

 care has been taken not to give too much trouble to the young 

 bees in their first attempt at coming to the light. When the 

 roof and general wall of the nest was constructed, a slit was 

 left low down near each cell, and it forms a kind of door, hidden 

 very carefully by rather soft sand or cement. 



It is very remarkable that this insect should not always build 

 up its nest in the same manner, and that it should occasionally 

 use the ruins of last year's nests for the foundation and walls 

 of the new. Old and more or less broken down nests, which 

 contain vacant cells and the skins of the nymphs, frequently 

 remain attached to walls, and the Chalicodoma, when exploring, 



