296 Mr. 'P oulton' s fiirtJter experiments upon 



My conclusions as regards the modification of colours 

 of cocoons have been shown to be erroneous by Mr. 

 Bateson (Trans. Ent. Soc, 1891 and 18U2) ; although 

 there was no doubt about the colour-change itself. This 

 he has shown, in the cases of Eriofiaster lanestris and 

 Saturnia carpini, to be due to disturbance of the larvae, 

 and not to surrounding colours. It is probable that this 

 criticism affects the conclusions as regards other species 

 {Liparis aurijiiia and liumia cratceaata). It is likely, 

 however, that the principle still holds good in the genus 

 Halias, inasmuch as my earlier observations (Proc. Ent. 

 Soc, 1887, pp. 1, li) have been confirmed by Mr. Tutt's 

 recent publication ('Journal of Variation'), as well as by 

 a few experiments of my own during 1892, published in 

 this paper. The negative results of certain other experi- 

 ments upon cocoons are also given. 



The details of experiments upon the colours of the 

 imago are also recorded below. The species selected 

 was Gnoplios ohscurata, and the results were completely 

 negative. 



In certain cases the investigation of the susceptibility 

 of one stage has given information as to that of other 

 stages. Thus in the case of Gnoplios ohscurata, the colours 

 of the cocoon and of the larva were tested incidentally 

 in testing those of the imago. In such cases the chief 

 object of the research has determined the class into 

 which it has been placed in the arrangement adopted 

 below. 



B. Experiments upon Lepidopterous Larv^, 

 1886—1892. 



In the following arrangement the experiments upon 

 NoctiuB will be considered before those on Geometne, and 

 in each of these groups of experiments the order will 

 chiefly follow that of time, and also to some extent the 

 importance or completeness of the results, the earlier 

 and less satisfactory results being considered first. 



1. Experiments in 1886 vpon Mamestra brassicce, 

 Iladena olcracea, and Euplexia lucipara. — The experi- 

 ments were conducted upon captured larvte, and were 

 therefore far less satisfactory than those upon hatched 

 larva3. The progress of the investigation and its results 

 are most concisely given in a tabular form. 



