Bramble-Dwellers 



by a cause; and, as this cause acts invariably, 

 the same arrangement must be reproduced if 

 I renew the experiment. I renewed it, there- 

 fore, in the years that followed, with as many 

 appliances as I could find bramble-stumps; 

 and, at each new test, I saw once more what 

 I had seen with such interest on the first oc- 

 casion. If the number be even — and my col- 

 umn at that time consisted usually of ten — 

 one half goes out on the right, the other on 

 the left. If the number be odd — eleven, for 

 instance — the Osmia in the middle goes out 

 indiscriminately by the right or left exit. As 

 the number of cells to be traversed is the same 

 on both sides, her expenditure of energy does 

 not vary with the direction of the exit ; and the 

 principle of least action is still observed. 



It was important to discover if the Three- 

 pronged Osmia shared her capacity, in the 

 first place, with the other bramble-dwellers 

 and, in the second, with Bees differently 

 housed, but also destined laboriously to cut a 

 new road for themselves when the hour comes 

 to quit the nest. Well, apart from a few ir- 

 regularities, due either to cocoons whose larva 

 perished in my tubes before developing, or to 

 those inexperienced workers, the males, the 



46 



