312 Mr. ^onlton' 8 further experiments upon 



Dates. 



May 12 

 „ 17 



23 



Experiment I. 

 Dark Surround- 

 ings (dark twigs). 



10 introduced. 



Average length of 

 31'5 mm. in all ex- 

 periments. Larvffi 

 on the whole ra- 

 ther darker than 

 those in III. and 

 IV. 



All full-fed. As 

 before, slightly 

 darker than III. 

 and IV., but little 

 difcrence. 



Experiment II. 

 Dark Surround- 

 ings (dark twigs). 



9 introduced. 

 As in I. 



Full-fed. As in 



Experiment III. 

 Green Surround- 

 ings (leaves, &c., 

 alone). 



10 introduced. 



Distinctly but 

 not greatly lighter 

 when compared as 

 a whole with I. 

 and II. 9 alive. 



Full-fed, and 

 most of them seek- 

 ing pupation. 



Experiment IV. 

 Green Surround- 

 ings (leaves, &c. 

 alone). 



9 introduced. 

 As in III. 7 alive. 



Full-fed, and 1 

 seeking pupation. 



The fact that there was some noticeable difference 

 probably indicates considerable susceptibility, remem- 

 bering the late period at which the experiments began, 

 and the rapid growth which at once set in. It is likely 

 that these experiments will prove to be chiefly interesting 

 as showing, with some of those conducted upon A. hetii- 

 laria in 1892, the comparatively early stages during 

 which the colours of the mature larvae are determined in 

 species which possess the power of individual colour- 

 adaptation. 



14. Experiments in 1887 and 1888 upon Crocallis 

 elinguaria. 



1887. 

 A batch of eggs of this species, laid by one moth, was 

 sent me, in the autumn of 1886, by Professor Meldola. 

 They hatched in the following spring, and were at first 

 fed ]n a bottle, being offered privet, hawthorn, and lilac. 

 The latter food-plant was preferred, and, after April 25th, 

 was alone employed. The experiment was begun at this 

 date. The tabular form is unsuited to the notes taken. 



April 25. — The largest larvsc were about 15-0 mm. long ; 8 were this 

 size or rather smaller, while 4 were much smaller (about 8 mm. long), 

 and 1 intermediate between these two lots. 4 of the larger larvie and 2 

 of the smaller were placed in dark surroundings, while the remaining 7 

 were placed in green surroundings. The two small ones in the latter 

 were subsequently isolated, although the surroundings were still green. 



