lepidopterous larvae and pupae and their surroundings. 143 



II. Transference experiments. 



In order to find out to what extent the larvae were 

 susceptible after hibernation, some were taken from the 

 black surroundings in B, and given white sticks as in C. 

 In the same way some were taken from C and put into a 

 case containing black sticks. The results are best shown 

 by a table. One curious point is that the white sticks 

 produced their full effect sooner than the dark ones, 

 whereas in the experiments on the early stages the reverse 

 was the case. 



TABLE II. 



III. Experiments on the pnipa of U. sambucaria. 



When the first of the larvae used on the previous 

 experiments began to spin, all were arranged in various 

 environments with a view to testing the susceptibility of 

 the pupae. In the first set (Table III) the larvae were 

 left in the same environments that they had hitherto 

 occupied. The results of this set show clearly enough 

 that when the same conditions are continued, the pupae 

 are as well adapted to them as were the larvae. What 

 they do not show is to what period of susceptibility the 

 adjustment is due. Prof. Poulton thinks that it is effected 

 just before pupation, and independently of the previous 

 environment of the larvae. The results shown in Table 



