388 D WIGHT E. MINNICH 



nation of 24 mc. than they did in one of 957 mc. Bees presenting 

 a number of negative d values, such as nos. 22, 25, 34, 41, 43, 55, 

 56, 62, 66, 85, 126, and 135, with one exception, showed an equal 

 or greater number of positive values. The exception noted was 

 bee no. 56. Three of the four pairs of determinations obtained 

 on this animal not only yielded negative differences, but differ- 

 ences of large magnitude as well. Bee no. 56, hke a number of 

 other individuals presenting a considerable number of negative 

 d values, varied considerably in its behavior and turned chiefly 

 toward the blackened eye. How far the disturbing factors thus 

 evidenced account for the results is not absolutely certain, since 

 a number of bees of apparently similar tendencies yielded posi- 

 tive values of d. Certainly, however, there are a number of 

 factors, particularly in the type of experiment under considera- 

 tion, which do interfere with the effect of photic stimulation. 

 Some of these serve to intensify the response, while others tend to 

 counteract or even completely annul it. Without attempting tO' 

 minimize the significance of these negative data in the least, I 

 believe some of them, probably all of them, find their explana- 

 tion in such factors. If this be correct, the negative results ob- 

 tained lie well within the range of variation which might be 

 expected in experimental work of this sort. A more extended 

 discussion of the factors responsible for variability of behavior in 

 the present experiments is presented in the next section of this 

 paper. 



The evidence in general, therefore, seems to warrant the con- 

 clusion that bees with one eye blackened tend to turn more toward 

 the functional eye in an illumination of 957 mc. than in one of 

 24 mc. This tendency may result in the animal's actually turn- 

 ing more toward the functional eye, or in its turning less toward 

 the covered eye, depending upon the idiosyncrasies of the indi- 

 vidual. In either case, however, with increased photic stimula- 

 tion, there is an increased tendency toward the functional eye. 

 The nature of the stimulus afforded by the apparatus employed 

 was continuous and of almost uniform intensity, and since the 

 circus movements of the honey-bee vary with the intensity of 

 such stimulation, they must be dependent upon it. These con- 



