PHOTIC REACTIONS OF HONEY-BEE 395 



behavior. In blackening the compound eye I made no attempt to 

 cover the ocelh, but afterward in examining the specimens used, 

 I found that sometimes all, sometimes only one or two, at other 

 times none of these organs had been covered. If the ocelli do 

 exercise any considerable function, therefore, there was involved 

 here a variable of no small magnitude. 



It is also possible that in bees other portions of the body, or 

 even the entire integument, may be photosensitive. Photoder- 

 matic sensitivity is not unknown among arthropods. It has 

 been reported by Graber ('84) for the cockroach, by Plateau ('87) 

 for two species of blind myriapods, and by Stockard ('08) for the 

 walking-stick. 



In order to find out if these several possibilities were affecting 

 results, I conducted several experiments with bees both eyes of 

 which had been carefully covered with a thick coat of 'Jap-a-lac' 

 On the morning after the operation, each bee was placed in a 

 separate cage in non-directive illumination of 957 mc. Although 

 with one or two exceptions the bees were quiet when first exposed 

 to the light, within fifteen minutes all had become thoroughly 

 active, showing clearly that they were not free from the activat- 

 ing effect of the light. 



At the conclusion of the above test the same bees were individu- 

 ally subjected to trials in the directive light area. Here they 

 looped and turned in a variety of ways, some circling more or less 

 constantly toward a given side, not unlike bees with only one 

 eye blackened. Despite most devious courses, however, they 

 sooner or later managed to work their way to the general region 

 of the source of light. It is quite clear, therefore, that photore- 

 ception had not been entirely abolished, although both com- 

 pound eyes had been covered as carefully as possible. 



Which of the several explanations advanced accounts for these 

 results, is not certain. I am disposed to believe that the failure 

 to eliminate the compound eyes completely was chiefly, perhaps 

 solely, responsible. However that may be, it is certain that in 

 this, as well as in other experiments, the incomplete suppression 

 of photic stimulation was the source of a large amount of varia- 

 tion in the results obtained. 



