Bramble-bees and Others 



The chambers presented by those old nests 

 are more or less spacious according to the 

 thickness of the coat of mortar which the 

 Chalicodoma has laid over the assembled 

 chambers. To leave her cell, the Mason-bee 

 has to perforate not only the plug, the lid 

 built at the mouth of the cell, but also the 

 thick plaster wherewith the dome is strength- 

 ened at the end of the work. The perfora- 

 tion results in a vestibule which gives access 

 to the chamber itself. It is this vestibule 

 which is sometimes longer and sometimes 

 shorter, whereas the corresponding chamber 

 is of almost constant dimensions, in the case 

 of the same sex, of course. 



We will first consider the short vestibule, 

 at the most large enough to receive the plug 

 with which the Osmia will close up the lodg- 

 ing. There is then nothing at her disposal 

 except the cell proper, a spacious apartment 

 in which one of the Osmia's females will find 

 ample accommodation, for she is much smaller 

 than the original occupant of the chamber, 

 no matter the sex; but there is not room for 

 two cocoons at a time, especially in view of 

 the space taken up by the intervening parti- 

 tion. Well, in those large, well-built cham- 



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