MASON-BEES. 39 



more durable edifices than those which have fallen 

 under our observation ; — for Reaumur says they 

 were harder than many sorts of stone, and could 

 scarcely be penetrated with a knife. Ours, on the 

 contrary, do not seem harder than a piece of sun- 

 baked clay, and by no means so hard as brick. One 

 circumstance appeared inexplicable to Re'aumur and 

 his friend Du Hamel, who studied the operations of 

 these insects in concert. After taking a portion of 

 sand from one part of the garden-walk, the bees 

 usually took another portion from a spot almost twenty 

 and sometimes a hundred paces off, though the sand, 

 so far as could be judged by close examination, was 

 precisely the same in the two places. We should be 

 disposed to refer this more to the restless character 

 of the insect, than to any difference in the sand. 

 We have observed a wasp paring the outside of a 

 plank, for materials to form its nest; and though the 

 plank was as uniform in the qualities of its surface, 

 nay, probably more so than the sand could be, the 

 wasp fidgeted about, nibbling a fibre from one, and 

 a fibre from another portion, till enough was procured 

 for one load. In the same way, the whole tribe of 

 wasps and bees flit restlessly from flower to flower, 

 not unl'requently revisiting the same blossom, again 

 and again, within a few seconds. It appears to us, 

 indeed, to be far from improbable, that this very rest- 

 lessness and irritability may be one of the springs 

 of their unceasing industry. 



By observing, with some care, the bees which we 

 found digging the clay, we discovered one of them 

 (Osmia bicornis) at work upon a nest, about a gun- 

 shot from the bank. The place it had chosen was 

 the inner wall of a coal-house, facing the south-west, 

 the brick-work of which was but roughly finished. 

 In an upright interstice of half an inch in width, be- 

 tween two of the bricks, we found the little architect 



i>2 



