REACTIONS TO LIGHT IN VANESSA ANTIOPA 399 



results secured by Hadley with larval lobsters. He found that 

 these animals, at all ages, moved in circles toward the blinded eye, 

 although they vary in the sign of their reaction to light at differ- 

 ent ages. He says ('08, p. 197): "In the lobster larvae all the 

 progressive reactions which took place immediately following the 

 blinding of one eye were positive. In certain cases it appeared 

 that either the operation itself, or the effects of blinding changed 

 the index of reaction from negative to positive. In all these 

 instances, whether the previous reaction had been negative or 

 positive, the resulting behavior was the same; a series of revo- 

 lutions, or circus movements, or a progression in which the direc- 

 tion of turning indicated that the influence of light on the 

 unblackened eye was to cause greater activity of the swimming 

 appendages on that side of the body, while blinding invariably 

 had the opposite effect. In other words, the reaction of the 

 bhnded positively reacting lobster larvae corresponds with those 

 of Holmes's negatively reacting amphipod, Hyalella dentata 

 (Smith) but not with his positively reacting amphipods." 



Hadley is the only investigator who records continuous move- 

 ments only toward the non-functional eye in individuals both in 

 the positive and in the negative state. It is therefore probable 

 that the circus movements described by him were due not to the 

 withdrawal of the light stimulus from one eye, but to the stimu- 

 lation produced by searing the eye with a hot needle, which was 

 the method used by him in blinding his animals. These experi- 

 ments ought to be repeated and the organisms tested on succeed- 

 ing days. Besides, this method of blinding the lobster should 

 be supplemented by entirely cutting off the eye stalk and testing 

 for several days in succession the young lobsters so operated on, 

 thus eliminating the possible effect of injury on the response. 



D. BEHAVIOR IN NON-DIRECTIVE LIGHT 



In the preceding pages we have discussed the behavior of 

 Vanessa in a horizontal beam of light, and in the absence of light. 

 We shall now describe its reactions in a field uniformly illumi- 

 nated from above. When the butterflies are placed in a beam 

 of light, all of the light that reaches them emanates practically 



