368 



THE INSECT WOELD. 



that the head of the young is always turned downwards, in 

 such a way that it is by the bottom of its cell that it comes 

 out. The bottom of the first is very near the surface of the 

 wood, so that the insect it encloses has only a thin layer of wood 

 to pierce through in order to set itself free. Each one of 

 those which are born next has only to pierce the floor of its 

 hiding-place to find the road before them free. The Xylocopce 



the wiutti in the pupa state, and the perfect insects, with 

 wings of a beautiful metallic violet, appear in the spring, but are 

 not found in this country. 



Other solitary bees have their hind legs unsuited for the gather- 

 ing of pollen, but have the rings of the abdomen furnished with 

 haijrs for thai purpose. Such are the Mason bees of Reaumur, 

 belonging to the genera Osmia and Chalicodoma* which build their 

 nests against walls of tempered earth, which become very hard. 



* At a meeting of the Entomological Society of London, Feb. 18th, 1867, Mr. 

 Newman exhibited the lock of a door, one of several which, in 1866, were found at 

 the Kent Waterworks, Deptford, to be completely filled and choked up with nests of 



