The Mason-bees 



fore, accumulate at random in this work-yard 

 where there is no organization. Their shape 

 is that of a thimble divided down the mid- 

 dle; and their walls are completed either by 

 the adjoining cells or by the surface of the old 

 nest. Outside, they are rough and display 

 successive layers of knotted cords correspond- 

 ing with the different courses of mortar. In- 

 side, the walls are flat without being smooth; 

 later on, the grub's cocoon will make up for 

 any lack of polish. 



Each cell, as built, is stocked and walled up 

 immediately, as we have seen with the 

 Mason-bee of the Walls. This work goes on 

 throughout the best part of May. All the 

 eggs are laid at last; and then the Bees, with- 

 out drawing distinctions between what does 

 and what does not belong to them, set 

 to work in common on a general protection 

 for the colony. This is a thick coat of mor- 

 tar, which fills up the gaps and covers all the 

 cells. In the end, the common nest presents 

 the appearance of a wide expanse of dry mud, 

 with very irregular protuberances, thicker in 

 the middle, the original nucleus of the esta- 

 blishment, thinner at the edges, where as yet 

 there are only newly-built cells, and varying 

 28 



