60 Studies in Animal Behavior 



light with equally definite swaying movements of the 

 body. If the light is to one side the legs on that 

 side are flexed and the opppsite legs extended. Pass- 

 ing the light over the body causes the reverse at- 

 titude. Hold the light in front of the body and 

 the insect bows down in front in an attitude of ab- 

 ject submission. Carry the light behind the insect 

 and it elevates the anterior part of its body and 

 holds its head high in the air. These bodily atti- 

 tudes are assumed with almost machine-like regular- 

 ity. For each position of the light there is a cor- 

 responding position of the head and body. 



After a little Ranatra will follow the movements 

 of the light by walking slowly and awkwardly toward 

 it, gradually increasing the vigor and rapidity of 

 its response until it will rush toward the light with 

 frenzied haste. It becomes oblivious to all else but 

 the light, which seems to dominate its behavior en- 

 tirely. If the source of light gives off a good deal 

 of heat the insect will continue to go toward it until 

 overcome by the heat. I have seen Ranatras when 

 nearly killed by the heat of the lamp toward which 

 they were attracted, slowly drawing themselves with 

 the last remnants of their strength a little nearer 

 to the fatal source of light. 



Nothing could seem more mechanical or more ob- 

 viously the result of domination by outer agencies 

 than the phototaxis of this form. There are, how- 

 ever, some curious features of the behavior of 

 Ranatra which are disclosed by other experiments 



