CHEMICAL SENSITIVITY OF TAKSI OF PYRAMEIS 61 



the death feint, although this reaction is virtually negligible in 

 Pyrameis; 2) to eliminate the immediate effects of mechanical 

 manipulation incident to the trial; 3) to accustom the animal to 

 the grip of the holder on the wings, and, 4) to make certain that 

 there was no sign of proboscis extension in the absence of the 

 chemical stimulus to be applied. The last-mentioned point is of 

 particular importance, for extensions of the proboscis were 

 occasionally observed when no external chemical stimulus was 

 apparent. Responses of this sort were most frequently observed 

 in individuals which, through prolonged starvation, had become 

 extremely sensitive. Most of these responses w^ere of slight 

 magnitude, although some consisted of complete extensions. The 

 following examples will illustrate the cases in point. 



In all trials butterflies were manipulated by means of a spring 

 clothes-pin in which the wings were firmly held. The most 

 simple method of placing an animal in the holder was often by 

 direct use of the hands. This involved grasping the wings, and 

 later the thorax and wing bases with the fingers. On grasping 

 the wings with the fingers, as the specimen was pulled off the wall 

 of the cage where it had been resting, there was occasionally a 

 shght jerk of the proboscis coil. Again, while the butterfly was 

 being held by the fingers in one position or another, further 

 incomplete or, in rare instances, complete extensions of the pro- 

 boscis were noted. Because of these occasional responses, direct 

 contact between the hands and the body of the animal was 

 avoided whenever possible. But even when the holder was 

 applied directly to the wings, there were one or two instances of 

 response. The stimuli effecting these responses cannot be postu- 

 lated with certainty. I am inclined to believe that distance and 

 contact chemical stimuli from the hands were chiefly responsible 

 although it is possible that in conditions of extreme sensitivity 

 mechanical stimuli may also exert some influence. 



In several instances a butterfly which had remained undis- 

 turbed in its cage fifteen minutes or more was found exhibiting 

 either a partial or complete extension of the proboscis. The pre- 

 vious trial having been completed fifteen to twenty minutes 

 before, it was impossible to interpret such a case as a persisting 



