the colonrs of certain Lepidoj)tera. 295 



publication of the fullest detail, at any rate as regards 

 many of the species first investigated. When the prin- 

 ciple has been proved, the same evidence is not necessary 

 in all cases. 



I am now therefore bringing together the results of all 

 my notes of these experiments upon lepidopterous larvae, 

 omitting those upon the SxjhingicUe. These details, to- 

 gether with the confirmatory results obtained by Mr. 

 Perkins u])on Boarmia rhomhoidaria (unpublished), and 

 by Miss Gould and Mr. Bateson as pulilished in these 

 Transactions for the present year (pp. 215 and 205), will, 

 I think, leave no room for doubt as to the importance and 

 j)revalence of this principle as regards Lepidoptera. It 

 will be interesting in the future to test its applicability to 

 other species, but the greatest interest and importance 

 now attaches to the attempt to acquire further knowledge 

 of the physiology of the process. Certain solid contri- 

 butions (so far as they go) towards this end will bo 

 found in tlie subsequent experiments, and especially those 

 upon Amphidasis hetidaria in the present year (1892). 



As regards the susceptibility of certain exposed pupse, 

 I began to experiment in 1886 upon Vanessidce and 

 Pierid(s (Phil. Trans. Eoy. Soc, vol. 178 (1887), B, 

 pp. 311 — 441). Since then I have again experimented 

 upon the same species, as well as others, but, as in the 

 larvte, only the most general statement of results has 

 been made (' Colours of Animals,' pp. 110 — 142). The 

 details now published, together with the confirmatory 

 results obtained by Mr. G. C. Griffiths (Trans. Ent. Soc, 

 1888, p. 247), Eev. J. W. B. Bell, Mr. Pembery (both in 

 'Midland Naturalist,' Dec, 1889, pp. 289, 290), Mr. 

 W. H. Jackson (Linn. Soc. Trans., vol. v., 1890, jjp. 156, 

 157), Mr. P. C. Mitchell, quoted by Mr. Jackson (I.e.), 

 Mr. Bateson (these Transactions, 1892, p. 205), Mr. 

 Merrifield (Proc. Ent. Soc Lond., 1892, p. xxx), 

 will leave no doubt about the importance of the prin- 

 ciple as regards exposed pupae of Lepidoptera, and here, 

 too, future w^ork will best be concentrated upon the 

 attempt to make out the physiology of the process. Li 

 this case, however, far more has been done, as will be 

 seen by an examination of my previous paper (Trans. 

 Eoy. Soc, I.e.), and the details of experiments during 

 1892 upon Vanessa io and T"". urticce which are to be 

 found in this paper. 



