Experiments 



It is therefore fully established that the 

 Mason-bee of the Walls, carried to a distance 

 of two and a half miles and released at a place 

 which she has certainly never seen before, is 

 able to return to the nest. But why do first 

 one out of two and then two out of five fail 

 to join their fellows ? What one can do cannot 

 another do ? Is there a difference in the faculty 

 that guides them over unknown ground? 

 Or is it not rather a difference in flying- 

 power? I remember that my Bees did not all 

 start off with the same vigour. Some were 

 hardly out of my fingers before they darted 

 furiously into the air, where I at once lost 

 sight of them, whereas the others came drop- 

 ping down a few yards away from me, after a 

 short flight. The latter, it seems certain, 

 must have suffered on the journey, perhaps 

 from the heat concentrated in the furnace of 

 my box. Or I may have hurt the articulation 

 of the wings in marking them, an operation 

 diflficult to perform when you are guarding 

 against stings. These are maimed, feeble 

 creatures, who will linger in the sainfoin-fields 

 close by, and not the powerful aviators re- 

 quired by the journey. 



The experiment must be tried again, tak- 

 47 



