the colours of certain Lcjndoptera. 453 



E. Experiments upon Lepidopterous imagines, 1891. 



1. Experiments in 1891 upon the colours of the larvce, 

 cocoons, and imagines of Gnophos ohscurata. — I have been 

 anxious to experiment upon this species for many years, 

 but, until 1891, I was unable to obtain the material. 

 I have suggested a probable influence of environment in 

 determining the colours of the imago, vi^hich is well 

 known to be light-coloured on chalk, and dark on peat 

 ('Colours of Animals,' Internat. Sci. Ser., pp. 157, 158). 

 The colours of these local varieties are certainly pro- 

 tective ; for Mr. W. E. Nicholson, of Lewes, who has had 

 a very wide experience of the species, tells me that the 

 imago always rests upon the bare ground by day, 

 although found on the grass if searched for with a 

 lantern at night. This is equally true on chalk and 

 peat, the moth usually resting on the face of pits or 

 banks, beneath ridgea or overhanging tufts of vegetation. 

 My friend Mr. Merrifield, of Brighton, knowing of my 

 wish to experiment with the species, kindly suggested to 

 Mr. Nicholson to obtain some larvfe for me. I wish to ex- 

 press my sincere thanks to both these gentlemen for their 

 kind help, which enabled me to carry out an investigation 

 I had especially looked forward to, and which was of 

 very great interest, although the results obtained were 

 negative. 



I received 20 larviB from Mr. Nicholson on May 16, 

 1891. These will be called the larvte of the ''first lot." 

 They were obtained by searching with a lantern on the 

 night of May 14, and all were resting on dry grass bents 

 on a steep chalk bank near Lewes, facing S.W. The 

 ground was very white, and the moth when taken in the 

 neighbourhood is very light ; in fact, the bank just 

 mentioned is the best locality for the almost pure white 

 variety of the species. 



Mr. Nicholson also sent me 25 more larvfe, — the 

 "second lot," — captured on the night of May 22 in the 

 same locality. 



Although the results were negative, I will give some 

 account of the experiments, for the value of the con- 

 clusions depends upon the very great care which was 

 exercised. The same methods may also be of use in 

 other species. 



