The Mason-bees 



ing count only of the Bees who start off 

 straight from between my fingers with a clean, 

 vigorous flight. The waverers, the laggards 

 who stop almost at once on some bush shall 

 be left out of the reckoning. Moreover, I 

 will do my best to estimate the time taken in 

 returning to the nest. For an experiment of 

 this kind, I need plenty of subjects, as the 

 weak and the maimed, of whom there may be 

 many, are to be disregarded. The Mason- 

 bee of the Walls is unable to supply me with 

 the requisite number: there are not enough of 

 her; and I am anxious not to interfere too 

 much with the little Aygues-side colony for 

 whom I have other experiments in view. For- 

 tunately, I have at my own place, under the 

 eaves of a shed, a magnificent nest of Chali- 

 codoma sicula in full activity. I can draw to 

 whatever extent I please on the populous city. 

 The insect is small, less than half the size of 

 C. muraria, but no matter : it will deserve all 

 the more credit if it can traverse the two miles 

 and a half in store for it and find its way back 

 to the nest. I take forty Bees, isolating them, 

 as usual, in screws of paper. 



In order to reach the nest, I place a ladder 

 against the wall : it will be used by my daugh- 

 4» 



