the colours of certain Lepidoptera. 319 



These results show that the hirvpe are very sensitive to 

 the colours of their normal surroundings. This was the 

 first species in which green and hrown environments 

 had respectively produced green and hrown larvse. In 

 others the former had merely produced very light hrown 

 larvse, and this is still true of the great majority of 

 species as yet tested. The results determined me to 

 conduct the same experiment more carefully and on a 

 larger scale in the succeeding year. 



It is interesting to observe that, although there was so 

 marked a difference between the larvre in I. and II., con- 

 siderable individual differences were noticeable in each 

 set. The sets varied in the amount or distribution of 

 darkness and greenness respectively, and in the amount 

 and distribution of " bloom." Although the conditions 

 were the same for each set, the larvfe reacted rather 

 differently, according to their individual predispositions. 

 I find this to be the case in many species, but the results 

 become more and more uniform as the conditions are 

 applied earlier, and as care is taken thjit they shall be as 

 extreme as possible throughout. But when every pre- 

 caution is taken, occasional exceptions show that there 

 are sometimes strong individual differences of predis- 

 position. This will appear in some of the experiments 

 on Amphidasis hetularia. 



1887. 

 {See Table, pages 320, 321.) 



These larvse were shown at the British Association at 

 Manchester, and a brief summary of the result is printed 

 in the Keport of the Meeting (see Keport, 1887, p. 756 ; 

 also 'Nature,' vol. 36, p. 594). Professor Weismann, 

 who was staying with me before the meeting, compared 

 them carefully ; he subsequently alluded to them in his 

 essay, " On the Supposed Botanical Proofs of the Trans- 

 mission of Acquired Characters " (1888). See Weismann, 

 " On Heredity," Oxford, vol. i., 2nd edition, pp. 406, 407. 



One of the chief interests is, however, due to the fact 

 that the moths produced by the larvae of Experiments II. 

 and III. paired and laid eggs, providing the material for 

 the next year. As the larvse of II. had been made dark 

 by their surroundings, and the larvae of III. green, and 

 as the offspring of both were subjected to both these con- 

 ditions, the test of any hereditary result was unusually 

 complete. 



