( civ ) 



upper side deep salmon-red with black borders and spots, the 

 other, P. sesamus, violaceous blue streaked with black, and 

 with a continuous series of salmon-red spots.* 



Affects general colouring. 



The effect to which I am calling attention is one which 



shows itself especially in the ground colour and general 



colouring of the wings and body. It may be stated as 



follows : — The higher temperature tends to produce a light 



yellowish brown passing on to chestnut or ochreous and 



orange, the low temperature dark, and in places blackish 



brown, the darkening effect showing itself in general, not 



merely in the ground colour, but also in some or most 



of the clouds and spots of different colour that diversify it, 



giving it in some cases, where these spots consist of single scales, 



the appearance of increased irroration. This kind of difference 



(frequently associated, in the facies presented by an insect 



subjected to severe or lengthened exposure, with the more 



deep-seated and often much more striking change of pattern 



and colour above referred to as arising out of a hereditary 



predisposition that is merely awakened by the stimulus) I 



have found in Lepidoptera, so widely separated from each 



other as P. machaon, A. cratccgi, E. cardamines, L. sybilla, 



P. atalanta, P. cartlui, V. urticx, V. polychloros, Polygonia 



c-albv/m, Meliteea aurinia, M. cinxia, M. didyrna, Argynnis 



paphia, Zephyrun betidve, Orgyia antiqua, Lasiocampa quercus 



* Mr. Trimen's Presidential Address, Proc. Ent. Soc, 1898, p. lxxii, 

 which gathers together all the knowledge on " seasonal dimorphism " up 

 to that date, since which important additions have been made especially 

 by Mr. Guy K. A. Marshall,1896-1901. See the joint paper below referred 

 to pp. 287-585 ; also Dr. Dixey, in Trans. Ent. Soc. 1902, pp. 189-21 8, and 

 Proc. Ent. Soc. 1902, pp. xv-xviii, on Mr. Loafs collection, Proc. Ent. Soc. 

 1903, pj). xi-xiii, and Trans, pp. 141-164 ; Poulton, l'roc. Ent. Soc. 

 1903, pp. xxxii-xxxiv ; and Lathy, Trans. Ent. Soc. 1903, pp. 183-206. 

 As to the protective value of the different colouring — extending also to 

 habits — of the two forms of this species of Precis, see Mr. Guy A. K. 

 Marshall and Professor Poulton's joint paper, Trans. Ent. Soc, 1902, p. 

 424 et seq. In the case of A. Icvana, I do not know that more can be 

 said than that there is probably something advantageous to a summer 

 butterfly in the general colour and pattern on the upper side, combined 

 with powerful flight, that is common to so many of them (Limenitis, 

 Apatura, Sato/rids), and thai tin.' summer form, prorsa, of levana, has a 

 great resemblance to them in all these respects. And such of these external 

 appearances as are not in themselves useful, may be the outward and 

 visible signs, the correlatives, of physiological adaptations beyond our ken. 

 (See Professor Meldola's Presidential Address, Proc. Ent. Soc, for 1896 ) 



