300 Mr. 'Ponlton^ 8 further experiments upon 



These results are also unsatisfactory. I cannot point 

 with any confidence to the colours of larvae which had 

 died in the course of the experiments, for the existence of 

 ahnormal conditions is only too evident. It is probable 

 that such conditions are to be found in the numbers 

 of the larvae in these and the previous experiments. 

 Having regard to the habits of the larvae, in future 

 work it will be well to place very few in each cylinder or 

 case. 



The results, however, clearly call for further work, 

 and seem to hold out some hope of positive results. In 

 one respect, however, negative results of much interest 

 are to be gained from the experiments here recorded. 

 In dimorphic (green and brown) species the change from 

 one colour to another in the lifetime of an individual 

 takes place, at any rate as a rule, rapidly in the transi- 

 tion from one stage to another. The larva changes its 

 skin and assumes the other colour. Now, the analogy 

 of the pupal changes of colour made it worth inquiring 

 whether the larva was susceptible to the colours on 

 which it rested during the period before ecdysis. Certain 

 observations were directed to test this possibility in both 

 these and the former series of experiments. In 1 the 

 results were consistent with the existence of such 

 susceptibility, but the evidence was far from strong, 

 inasmuch as the conditions of the larvae observed were 

 such as to correspond with the general tendency to 

 become brown in the last stage. In these experiments 

 the results are clearly negative, and seem to prove, so far 

 as this species is concerned, that no susceptibility exists 

 at the time in question. In Experiment I. it is recorded 

 that 2 green larvae were resting, during the last ecdysis, 

 on green leaves, and 1 became brown ; while of 3 green 

 larvae similarly resting on brown surfaces, 2 became 

 green. 



3. Experiments in 1888 upon Catocala sponsa. 



This experiment was conducted in the early summer 

 of 1888. The larvae were reared from eggs obtained by 

 George Tate, of Lyndhurst. The food-plant employed 

 was oak. 



