PHOTIC REACTIONS OF HONEY-BEE 377 



light. Throughout a single series of consecutive trials, or, as I 

 shall call it, a determination, one intensity of light only was 

 employed. But in the total number of determinations the more 

 intense illumination of 957 mc. and the less intense of 24 mc. were 

 used an equal number of times. The animal to be tested was first 

 removed from the dark box and exposed from half a minute to 

 several minutes in the intensity of light in which it was to be 

 tried. This was usually sufficient to activate the animal thor- 

 oughly, and several records were then made in the non-directive 

 light chamber. In case the bee failed to respond to photic acti- 

 vation, recourse was had to mechanical stimulation. The cage 

 was tapped or even shaken fairly vigorously until locomotion 

 was induced. This procedure seldom failed to elicit activity. 

 When it did fail, it was usually necessary to discard the animal 

 altogether. 



The number and duration of the records comprising a single 

 series or determination varied widely even in the same animal. 

 If the bee quickly encountered the side wall of the light chamber, 

 records were short, and a number had to be taken. If, on the 

 contrary, the animal kept well toward the center of the floor of 

 the apparatus, one or two records were quite sufficient. In cases 

 of great variability of response or unusual departures from the 

 general, expected behavior, additional trials were made, on the 

 assumption that a greater number would more accurately ex- 

 press the average tendency of the animal. Single trials seldom 

 exceeded thirty seconds, and were often much shorter. Occa- 

 sionally, however, records of forty-five seconds, sixty seconds, 

 or even slightly greater durations were taken. The aggregate 

 duration of the trials comprising a single determination, for one 

 intensity of light, was usually in the neighborhood of thirty or 

 sixty or ninety seconds. The adoption of any more uniform 

 period for all animals, at all times, was quite impossible. 



Upon completion of a series of trials in one intensity of light, 

 the bee was returned to the dark box. Here it was allowed to 

 remain for a period of about fifteen minutes to one hour. In the 

 earlier experiments the longer period was practiced ; in subsequent 

 experiments, the shorter. After this period in the dark, the ani- 



