334 J. D. DODSON 



TABLE 4 



Results of Experiments of Set II, Strong Stimulus 



(Volt. 19.5, Amp. 3.5) 



Special conditions of set III. The nest box and entrance 

 chamber were lined with black cardboard and the electric boxes 

 were lined with white. The openings over the electric boxes 

 were cut out till they were 40 by 18 cm. and the nest box and 

 entrance, chamber were covered with cardboard all but an open- 

 ing 20 by 40 cm. Thus the condition of visual discrimination 

 was made fairly easy. The stimuli used were the same as in 

 the previous experiments, but with one additional stimulus. 



