TARSAL CHEMORECEPTORS OF BUTTERFLIES 177 



In the laboratory the butterflies were housed in large cages, 

 the largest being 1 m. x 1 m. x 1 m. These were constructed of 

 light wooden framework, covered with mosquito bar. Under 

 these conditions, Pyrameis lived from three to four days without 

 food or water. This period undoubtedly depends much upon 

 temperature and the consequent rate at which water is lost 

 through evaporation. During these experiments the weather 

 was extremely warm and the windows of the laboratory were 

 kept open. At a lower temperature the less rapid loss of water 

 would probably increase the longevity considerably. Properly 

 fed, Pyrameis survived longer, but needed to be fed regularly 

 every few days in order to survive in good condition. Vanessa, 

 however, proved a much hardier animal, surviving a period of 

 ten days or even considerably longer without food or water. 



Individual butterflies were easily distinguished by clipping 

 the wings slightly, in different ways, and numbering the animals 

 accordingly. A spring clothes-pin, from which the beveled tips 

 had been cut off, was employed as a holder to handle the animals. 

 This served the purpose well, holding the animal firmly and at 

 the same time permitting easy manipulation. 



The grip of the holder on the wings, however, together with 

 the manipulation involved in placing the animal in the holder, 

 induced the death feint in both species. In the case of Pyrameis 

 this reaction was not very pronounced, and even in the most 

 extreme cases it was sufficient to bring the feet in contact with 

 a substrate a few seconds for the animal to recover completely. 

 Once the death feint had worn off, moreover, the butterfly 

 remained active and responsive. 



With Vanessa, however, the death feint was prolonged and 

 sometimes very difficult to overcome. It was found that 

 recovery could be hastened by genth^ dragging the feet of the 

 animal over a surface, and this was done prior to each trial. 

 But even after this procedure, the removal of the animal a short 

 distance to the place where it was to be tested often induced more 

 or less of the death feint again. Whenever an animal failed to 

 respond to chemical stimulation in the first part of a trial, there- 

 fore, it was gently lifted and set down several times in succession, 



