TARSAL CHEMORECEPTORS OF BUTTERFLIES 



183 



are permitted to come in contact with applejuice, the number 

 of responses is enormously increased. In other words, in a large 

 number of cases in which the butterflies do not respond either 

 to distance stimuli or to distance stimuli plus the contact stimulus 



00':^ 



29% 



17' 



I 2 3 



Fig. 2 Graph showing the percentage of responses obtained from specimens 

 of Pyrameis, when subjected to the same number of trials in positions 1, 2, and 3 

 on the apparatus shown in figure 1. 



of distilled water on the second tarsi, they do respond to distance 

 stimuli plus the contact stimulus of applejuice on the second 

 tarsi. Clearly, therefore, the second tarsi are sensitive to con- 

 tact chemical stimulation and must contain appropriate receptors 

 therefor. 



