Bramble-bees and Others 



sometimes two round apertures that looked as 

 though they had been punched out with an in- 

 strument. On opening these stalks, which 

 were old, deserted nests, I discovered the cause 

 of these very exceptional windows. Above 

 each of them was a cell full of mouldy honey. 

 The egg had perished and the provisions re- 

 mained untouched: hence the impossibility of 

 getting out by the ordinary road. Walled in 

 by the insurmountable obstacle, the Osmia on 

 the floor below had contrived an outlet 

 through the side of the shaft; and those in the 

 lower storeys had benefited by this ingenious 

 innovation. The usual door being inaccessi- 

 ble, a side-window had been opened by means 

 of the insect's jaws. The cocoons, torn, but 

 still in position, in the lower rooms, left no 

 doubt as to this eccentric mode of exit. The 

 same fact, moreover, was repeated, in several 

 bramble-sticks, in the case of Osmia trident- 

 ata; it was likewise repeated in the case of 

 AntJnd'unn scapidare. The observation was 

 worth confirming by experiment. 



I select a bramble-stem with the thinnest 

 rind possible, so as to facilitate the Osmis's 

 work. I split it in half, thus obtaining a 

 smooth-sided trough which will enable me to 



27 



