OBSERVATIONS ON THE BEHAVIOR OF BUTTERFLIES 251 



control. In earlier papers I have expressed the conviction that 

 much of such artificial work has been far from convincing, 

 and some of it actually mischievous. It may be probable that 

 some of this failure attaches to study of lepidopteran behavior ! 



My observations began with the study of Vanessa antiopa, 

 and were chiefly directed to that species, but several other 

 species also came in for a share of attention. The following 

 points will be emphasized: (1) Marked individual differences 

 of behavior under apparently identical conditions; (2) differences 

 at various times of day, and various days; (3) marked sense of 

 locality and adherence thereto; (4) lack of evidence of any sex 

 adaptation in the color markings as related to behavior. 



My observations confirm those of Parker, (1) as to the domi- 

 nance of ' chemotropic response to food;" (2) the general 

 negative phototropism in strong sunlight; (3) general indiffer- 

 ence of butterfly to shadow stimuli except in the head region. 



My first notes on the behavior of Vanessa were made on a 

 bright, warm day, the 25th of March. The first two specimens 

 found were very wary and difficult to approach, but two other 

 specimens proved less wild, and allowed easy approach and 

 close observation and experiment. Several others were found 

 later which also allowed approach and similar observation. One 

 of these specimens alighted on an exposed snow-bank, oriented 

 in the usual manner, seemingly not at all disturbed by the 

 icy substratum on which it rested. In all some twenty careful 

 observations were made in relation to the particular orienting 

 behavior, and in general conformed fairly constantly to the 

 results obtained by Parker. As a basis on which to estimate 

 the degree of exactness of the orientation I regarded any reac- 

 tion which did not vary more than ten degrees from the precise 

 line of the sun's rays as conforming to the law, while anything 

 beyond this was regarded as a departure, or failure to conform 

 to the law. This is, of course, a purely arbitrary way of esti- 

 mating the reaction, but unless one insists on mechanical pre- 

 cision in every case (a method which might be demanded), it 

 seems as good as one might propose. In the first series, just 

 given, the majority clearly behaved in conformity with expecta- 

 tion, but a number as clearly fell outside such expectation. In 

 this connection were noted facts which clearly illustrate the indi- 

 vidual difference of behavior, e.g., the differing susceptibility 



