the colours of certain Lepidoptera. 



B85 



The influence op Dark Surroundings in light as 



contrasted with the effects op darkness. 

 In my previous paper [I.e., pp. 364, 365) I bad made 

 a pair of experiments in order to test the relative 

 efficiency of black surroundings in light and in dark- 

 ness, the results favoured the latter, which, upon the 

 whole, produced somewhat darker pupae, although they 

 also included some which were lighter than the others. 

 The numbers were insufficient for any safe conclusion, 

 and I was therefore anxious to repeat the experiments 

 on a much larger scale, especially considering that larva 

 brought up in darkness are as a rule much less dark 

 than those brought up among dark surroundings in 

 strong light (see the earlier part of this paper). Hence 

 a far larger number of experiments were devoted to the 

 solution of this question than of any other. The 

 table at p. 384 shows tbe results of all such experiments 

 upon this species in 3 887 and 1888, omitting No. 5, the 

 arrangement of which is uncertain, and including the 

 pupae formed upon a darkish surface of perforated zinc. 

 Below, the percentages are placed one under the other, 

 and compared with the results obtained in 1886, and 

 with the single experiment in which a gilt surface 

 (embossed Dutch metal, Experiment 13) was used in 

 complete darkness. 



This table indicates that there is very little difference 

 between the pupae of o, ft, as compared with ^, b. a is 

 not much to be relied on, because of the small numbers 

 emi)loyed. As regards the darkest pupae, ft, c, and i are 

 practically equal, but there is a much smaller proportion 

 of C2)s in"/3. In other respects no great difference can 



