The Mason-bees 



hundreds, very often in many thousands, un- 

 der the tiles of a shed or the edge of a roof. 

 These do not constitute a true society, with 

 common interests to which all attend, but a 

 mere gathering, where each works for herself 

 and is not concerned with the rest, in short, 

 a throng of workers recalling the swarm of a 

 hive only by their numbers and their eager- 

 ness. The mortar employed is the same as 

 that of the Mason-bee of the Walls, equally 

 unyielding and waterproof, but thinner and 

 without pebbles. The old nests are used first. 

 Every free chamber is repaired, stocked and 

 sealed up. But the old cells are far from 

 sufficient for the population, which increases 

 rapidly from year to year. Then, on the sur- 

 face of the nest, whose chambers are hidden 

 under the old general mortar covering, new 

 cells are built, as the needs of the laying-time 

 call for them. They are placed horizontally, 

 or nearly so, side by side, with no attempt at 

 orderly arrangement. Each architect has 

 plenty of elbow-room and builds as and where 

 she pleases, on the one condition that she 

 does not hamper her neighbours' work; other- 

 wise she can look out for rough handling 

 from the parties Interested. The cells, there- 

 27 



