BEHAVIOR OF A PARASITIC BEE 385 



ally a bee would not stop when it reached the lower border of 

 the shadow, but would continue on into the shadow a short 

 distance and then either drop a few inches or fly to the lighted 

 roof of the cage. On yet rarer occasions, a bee would, on reach- 

 ing the lower border of the shadow, continue on into the shadow 

 and rest there. 



At 10.19 a. ;;/., a bee was noticed flying about the cage and 

 ho\Tring momentarily before each side. Presently it alighted, 

 on the ceiling, near the side of the cage opposite the one through 

 which the direct ra3^s of the sun were entering. It then crawled 

 along the ceiling, through the sunlight, to the shadow near the 

 window-side of the cage and then dropped a short distance and 

 repeated the hovering movements. That bee crossed the light 

 in every possible direction; sometimes flying in the direction 

 of the incoming rays, sometimes flying in the opposite direction, 

 and sometimes crossing the rays at various angles. 



Experiment 18. — .4/ 11.20 a. in., the room was darkened to 

 about the brightness of twilight. 



In a short time all of the bees had retired to the bottom of 

 the cage. The majority entered the mud cells. 



Experiment 19. — ^4 beam from an electric projecting lantern 

 was passed through the cage. On the lantern-side of the cage, 

 the beam was eight inches wide and six and three-fourth inches 

 high. On the opposite side the beam was eight by six and a half 

 inches. A water cell was used as a heat filter. All other parts 

 of the cage were in twilight brightness. 



This cage was watched continuously for fourteen minutes. 

 During that time only one bee moved about the cage. That 

 bee behaved as follows : Soon after the beam was projected 

 through the cage, that bee climbed from the shadow into the 

 bright patch on that side of the cage that was remote from the 

 lantern. It continued its upw^ard course until it had mounted 

 the sunny wooden cross-piece at the top of that side; it then 

 crawled clown the netting for several inches and returned to 

 the wooden cross-piece, along which it moved back and forth 

 for a few seconds. It then moved along this piece, towards 

 the right, until it reached a shadow. Returning to the light, 

 it moved downward across the netting until it encountered 

 the lower shadow, when it again crawled upward, across the 



