The reverse of this is not less conclusive. To a mason bee which was laying up food I would give a cell only just sketched out and unable to receive the honey paste. This cell, still damp from the constructor’s saliva, might or might not be accompanied by other cells, recently closed and containing an egg and honey. The bee, whose half-filled cell is thus replaced, seems greatly puzzled on arriving with her load at this shallow hollow offering no place for the honey. She will examine it, measure it with her eye, try it with her antennæ, and recognise its insufficient depth. For a time she hesitates, departs, returns, flies off again, and comes back in haste to dispose of her load. Her embarrassment is visible; I could not help saying inwardly: “Take some mortar—take some mortar, and finish your storehouse. It will only require a few moments to make it deep enough.” The bee was of a different opinion. She was laying in food, and food she must lay up, happen what might. She could not decide to lay aside the pollen brush for the mason’s trowel, and nothing could induce her to delay the harvest which occupied her in order to take up that work of building for which it is not the due moment. Rather would she seek another cell, in the desired condition, and will penetrate there to store the honey, even if received with fury by the owner. In fact, this happened. I wished her success, knowing myself to be the cause of this desperate act. My curiosity had turned an honest worker into a thief.