The attempt was also made to answer the second question whether the struggle 

 is decided by the conspicuousness of the pupa. First, as to conspicuousness in 

 form, pup;© were fixed to surfaces which unequally concealed them ; thus the rough 

 surfaces of stone and bark (rough-barked trees being almost invariably selected), 

 and the shelter afforded by overhanging leaves of nettle, concealed their rough 

 angular forms far more than the comparatively smooth surface of fences. Looking 

 at the table on page 907, it is seen that at Oxford butterflies only emerged from 

 pupae fixed to nettles, while in the Isle of Wight the mortality on fences 

 (9(J taken to 8 emerged), was enormously greater than on bark (135 to 84), walLs 

 (14 to 12), and nettle (20 to 15). When" therefore the pupa is suspended from a 

 surface against which it stands out conspicuously, it is in far greater danger than 

 when it is fixed to one upon which it is concealed. This result is inexplicable, 

 except on the theory that the sense of sight is important to enemies in the dis- 

 covery of the pupa3. 



Secondly, as to conspicuousness in colour. In Nature the golden forms of the 

 pupa of this species are produced upon nettle, the darker forms on walls, rocks, 

 fences, and probably bark ; furthermore the darkest varieties are produced on the 

 darkest surfaces. In fixing the pupae, part were distributed as they are in Nature, 

 whUe part w^ere given a reverse arrangement — dark forms being fixed to nettle, and 

 golden forms to black fences and dark surfaces of bark, &c. Some of the experi- 

 ments gave extremely positive results, in that the mortality among the latter pupas 

 was far higher than among the former ; other experiments were negative. Until 

 the whole of the experiments have been analysed in far more detail than has as yet 

 been possible, we cannot make any statement as to the general bearing of the 

 inquiry upon the danger or otherwise of conspicuousness in colour, although the 

 danger of conspicuousness of form has been shown to be conclusively proved. 



It may be supposed that the experiments were vitiated by the accidental loss 

 of the pupae. Many considerations, however, indicate that no serious error has 

 been introduced in this way. In the absence of enemies, in Switzerland, the pupae 

 remained suspended until they emerged or until we removed them, and this was 

 also the case in the places of small mortality in the Isle of "Wight ; in many places 

 the ground was bare, and a fallen pupa (always searched for) would have been 

 easily seen ; the hard caudal extremity was frequently left fixed to the supporting 

 surface ; the different results obtained on fences and on bark, &c., are manifestly in- 

 explicable on this ground, the means of fixation being the same. The act of 

 emergence was obviously a much severer test of our method of suspension than 

 that supplied by the motionless pupa ; and yet in a large proportion of cases the 

 empty pupal shell was found hanging to the support, and thus remained for days, 

 in spite of the fact that its lightness enabled each breath of wind to blow it about. 



In future inquiries we trust that a pupa with a wider colour variation than 

 7'. urticce may be available. All attempts to obtain the larva of Vanesm lo were 

 unsuccessful, but next year we hope to get it and test the bright green and dark 

 forms which its pupa assumes. Other excellent examples would be the bright 

 green, bone-coloured, and dark forms of the pupae of Fieris Jicqn and P. rapce, 

 \vhich have the further advantage of being available for experiment during the 

 winter. Through the kindness of Mr. F. Merrifield we shall be able to carry on 

 the inquiry with these latter and some other species during the winter of 1898-9, 

 when we hope again to appeal to the kindness of the President and Fellows of 

 Magdalen College for the opportunity of continuing the investigation begun during 

 the past summer in the College grounds. 



We also desire to acknowledge the kind assistance we have received from Miss 

 Drummond and Miss Sidgwick in taking notes of the Oxford pupae during our 

 absence in Switzerland, and from Miss Notley for much kind help in the Isle of 

 Wight. Professor H. F. Osborn, Professor F. 0. Bower, and Mr. Arthur J. 

 Evans also witnessed the experiments in the Isle of Wight, and oftered valuable 

 suggestions and criticism. 



The investigation, of which this is a brief epitome, was manifestly a preliminary 

 inquiry: it has nevertheless yielded far more definite results than we ventured to 

 hope for when we undertook it. 



