384 C. H. TURNER 



about on the floor, passing from sunlight to shadow and from 

 shadow to sunlight, with no apparent system. On leaving the 

 floor most of the bees flew, either directly or in a roundabout 

 way, to the netting on that side of the cage through which the 

 direct rays of the sun were entering. A few of the bees, on 

 leaving the floor, climbed up the left side of the cage. (This 

 side of the cage formed an angle of ninety degrees with the 

 side upon which the majority of the bees alighted.) Of the 

 few bees that climbed up the left side of the cage, some passed 

 up through the sunlight and others through the shadow. 



SERIES IV (MAY 5, 1911) 



Experiment i6. — .4/ lo.oo a. m., the cage, which had been in 

 diffuse daylight all morning, was placed in a sunny window in 

 such a manner that the window-side of the cage, the top and, ex- 

 cept for shadows cast by the framework of the cage, all other parts 

 of the cage were in the direct sunlight. 



At 10.05 ^- ^^•' seven bees were resting on or hovering near 

 the netting on the window-side of the cage and two were in the 

 sunlight on the floor. No bees were resting on any other' 

 parts of the cage. Bees flew about the cage in all directions, 

 frequently approaching the different sides of the cage, but never 

 alighting on any except the window-side. 



Experiment 17. — .4^ 10.08 a. m., the upper portion of the 

 window-side of the cage was covered with an opaque screen six 

 inches wide. This caused the upper part of the window-side of 

 the cage to be in the shadow ivhile the lower portion was in the 

 direct sunlight. Except that the shadow on the floor was wider, 

 the other parts of the cage were illuminated as in experiment 

 sixteen. 



Immediately the bees left the shaded portion of the "v^indow- 

 side of the cage. One ascended to the lighted top of the cage ; 

 while eight hovered near, rested upon or climbed up the sunny 

 patch on the window-side of the cage. When a bee climbing 

 upwards through the lighted portion of the side through which 

 the direct rays of the sun were entering reached the lower border 

 of the shaded portion of that side, it usually dropped back- 

 wards ; sometimes only an inch or two, at other times to the 

 floor, and repeated the performance over and over. Occasion- 



