378 C. H. TURNER 



with the male on her back. In one case she even partly re- 

 climbed the wire netting. 



In each case that I had the opportunity to watch from the 

 beginning to the end, the first stages in the act of copulation 

 always occurred in the direct sunlight. This might lead one 

 to think that, in nature, copulation always begins in the direct 

 sunlight ; but, such a conclusion would be erroneous. On one 

 occasion I found a pair in copulo, on the floor, with one half 

 of each body in the sunlight and the other half in the shadow. 

 At the same time, on another portion of the floor of the same 

 cage, I discovered a pair in copulo in the shade. On yet another 

 occasion, on the netting of one of the walls of a cage that had 

 been in diffuse daylight for several hours, I found a pair of these 

 bees in copulo. When that cage was placed in the room none 

 of the bees was mating. Since it was impossible for the direct 

 rays of the sun to reach the cage, we have here conclusive proof 

 that copulation may be begun and carried to completion in 

 diffuse daylight. 



DESCRIPTION OF EXPERIMENTS ON THE INFLUENCE OF LIGHT 



SERIES I (MAY 2, 1911) 



Experiment i. — The cage -was so arranged, in a window, 

 that the side towards the window, the side opposite the window, 

 the top and the bottom were in the sunlight. On the bottom of 

 the 'cage and on the side opposite the window were narrow bands 

 of shadow caused by the framework of the cage. 



In a few minutes five bees flew towards the window-side 

 of the cage and alighted thereon ; one of these rested four inches 

 from the top of the netting and the other four near the bottom. 



Experiment 2. — .4^ 8.45 a. ui., the above cage was rotated, 

 as gently as possible, through an angle of 180 degrees. This 

 caused the bees that had been resting in the sun on the window side 

 of the cage to be transferred to the side that was most remote from 

 the window. 



Immediately three of the bees left the sunny place on the 

 side of the cage most remote from the window and flew towards 

 the window-side of the cage and rested thereon, in the sunlight. 

 In a few seconds these three bees were joined by another bee 



