PHOTIC KEACTIONS OF HONEY-BEE 393 



Normal bees were allowed to creep on a strip of smoked paper 

 toward the 80-c.p. incandescent lamp. When, after creeping a 

 distance of about 60 cm., the bee reached a point 40 cm. from the 

 source of light, the lamp was extinguished. Not only was the 

 current turned off, but a screen was simultaneously placed before 

 the lamp, so that even the slight after-glow of the filaments was 

 eliminated. After ten seconds of total darkness the light was 

 turned on and the bee removed. Two to four records were made 

 of each of eleven animals in this manner. In not one case did 

 the bee fail to lose its orientation within at most a couple of 

 seconds after the extinction of the light. Often the loss of ori- 

 entation was almost, if not quite, simultaneous with the cessa- 

 tion of the stimulus. The deviation from the former orienta- 

 tion was sometimes marked by a pronounced tendency to turn 

 toward one side, with the result that the animal crept in circles 

 in the dark. At other times the bee merely wandered, turning 

 first in one direction, then another. Typical records of two ani- 

 mals are reproduced in figure 16. There is, therefore, no after- 

 effect of photic stimulation in the honey-bee, and this does not 

 account for any of the irregularities observed. 



c. Failure to eliminate photoreceptor. The difficulties in manipu- 

 lating bees necessitate relying upon a single operation to elimi- 

 nate completely the function of the compound eye. Although in 

 this operation great care was exercised to cover the eye com- 

 pletely with a heavy coat of paint, there is a possibility that in a few 

 cases this was not accomplished. Moreover, from the moment 

 the animal began to recover from the anaesthetic, the covered 

 eye was repeatedly subjected to vigorous scrapings by the front 

 leg of the same side. While the examination of a number of 

 animals after experimentation showed that this seldom resulted 

 in a removal of any of the eye covering, it probably succeeded in 

 doing so in a few cases. Occasionally, also, the varnish cracked 

 somewhat on drying. These unavoidable failures to keep the 

 compound eye entirely free of light, undoubtedly modified, to a 

 greater or less extent, not a few of the results obtained. 



Beside the failure to cover the eye, there is the possibility that 

 the three ocelli of the honey-bee are concerned in its photic 



