The Mason-bees 



tered by top thin a wall, have to suffer from 

 excess of heat in summer and of cold in win- 

 ter? 



Without arguing all this out, the Bee nev- 

 ertheless acts wisely. When all the cells are 

 finished, she builds a thick cover over the 

 group, formed of a material, impermeable to 

 water and a bad conductor of heat, which acts 

 as a protection at the same time against 

 damp, heat and cold. This material is the 

 usual mortar, made of earth mixed with 

 saliva, but on this occasion with no small 

 stones in it. The Bee applies it pellet by pel- 

 let, trowelful by trowelful, to the depth of a 

 centimetre^ over the cluster of cells, which 

 disappear entirely under the clay covering. 

 When this is done, the nest has the shape of 

 a rough dome, equal in size to half an orange. 

 One would take it for a round lump of mud 

 which had been thrown and half crushed 

 against a stone and had then dried where it 

 was. Nothing outside betrays the contents, 

 no semblance of cells, no semblance of work. 

 To the inexperienced eye, it is a chance splash 

 of mud and nothing more. 



*.39 inch. — Translator's Note. 

 23 



