REACTIONS TO LIGHT IN VANESSA ANTIOPA 367 



study of this phenomenon than has been done previously. More- 

 over, such a study should throw light on the question as to 

 whether or not the path of nerve impulses resulting in a given 

 reaction can be altered, as well as on the very important prob- 

 lem of modifiability in behavior in general. 



The mourning cloak butterfly, Vanessa antiopa, was chosen 

 to begin with because the results secured with this, animal by 

 Parker are widely known and frequently quoted. This work is 

 to be followed by a more general study of the phenomenon in 

 question. 



Before entering upon a discussion of these experiments I wish 

 to express my very sincere appreciation of the kindness of Pro- 

 fessor S. 0. Mast in suggesting this problem to me and in so 

 unselfishly aiding me throughout the course of the work. 



METHODS 



The butterflies used were all reared in the laboratory from 

 larvae secured from both the June and the August broods in 

 Massachusetts, New York, and Pennsylvania. No difficulty was 

 experienced in keeping them in excellent condition for long periods. 

 They were kept in the laboratory in a large glass case, and fed 

 on honey and a weak solution of maple syrup in water. At 

 frequent intervals the insects were picked up and dropped on 

 filter paper soaked in the latter sweet mixture. If the proboscis 

 was not extended at once, it was uncoiled with a pin, and when 

 once the tip touched the liquid, the animal continued to feed 

 until its abdomen was swollen to an extent which seemed dan- 

 gerous. Since these butterflies pass the winter in the imago 

 state, it is not surprising that six specimens lived from August 

 until the latter part of February. These were the survivors of 

 a lot of about thirty which were received at the same time. 

 Had proper care been taken, it is likely that nearly all would 

 have lived through the winter in the laboratory. The wings of 

 the butterflies were usually clipped to prevent their escape. This 

 was in no wise injurious, for animals with clipped wings lived 

 and thrived at well as those whose wings were intact, and they 

 behaved in the same manner. 



