PHOTIC REACTIONS OF HONEY-BEE 371 



when one eye is blackened. The features of behavior which are 

 important in this connection may be summarized as follows : 



1. In the honey-bee, light tends to induce activity; darkness, 

 to inhibit it. This response is dependent upon the continuous 

 action of photic stimulation. 



2. Isolated worker bees in an active condition exhibit strong 

 positive photptropism when flying or creeping. Temporary sup- 

 pressions of this response may occur, however. 



3. Normal bees when creeping in non-directive light usually 

 exhibit pronounced asymmetrical responses of constant or vari- 

 able index. Since essentially the same responses occur in total 

 darkness they are not fundamentally dependent upon photic 

 stimulation. They are probably, therefore, conditioned largely 

 by internal factors. 



VI. BEHAVIOR OF BEES WITH ONE EYE BLACKENED 



1. Directive light 



The previous investigations of circus movements have pointed 

 unmistakably to the generality of these responses among photo- 

 tropic arthropods. Positive animals with one eye covered tend 

 to circle toward the functional eye; negative animals, under the 

 same conditions, tend to circle away from the functional eye. 

 The honey-bee exhibits a striking positive phototropism. When 

 one eye is blackened, therefore, we should expect the bee to circle 

 toward the remaining functional eye. Such is indeed the case, 

 as Axenfeld ('99, p. 374) has previously shown. 



In my own experiments, bees thus operated upon were no 

 longer able to creep in a straight course toward a source of il- 

 lumination. Instead, their progress thither was marked by re- 

 peated loops. If the right eye was blackened, the bee looped to 

 the left; if the left eye was blackened, it looped to the right. 

 Moreover, it was possible by blackening one eye, then removing 

 the black and blacking the other eye, to cause a single individual 

 to perform circus movements first in one direction, then in the 

 ■opposite direction. 



