370 



3- Picridœ mid Papilionidœ. 



Corning to the development of the wings in the pupœ of 

 PieridcB and Papilionidœ, I am sorry to say that I ñnd no 

 difficulty in being short in my description. My hope and ex- 

 pectation that I should be able to discover a primitive pattern, 

 just as clear and as interesting as in the case of the Vanessidœ-, 

 have up to this moment been disappointed. Nevertheless I 

 feel absolutely conñdent in asserting that in these families the 

 development of the wing-colours and pattern takes just the same 

 course, and shows similar phenomena as in the Nymphalidœ. 

 Without any doubt a primitive pattern arises also here at a 

 very early period, on both sides of both wings, and remains in 

 existence till a few days before the emergence of the imago, 

 when the deñnite pattern enters upon the scene with the speed 

 of a chemical reaction. And here again the different colours 

 do not arise all at one time ; on the contrary, in this case also the 

 black makes its appearance some time after the other colours. 



Neither in Papilionidœ nor in Pieridœ, however, does this 

 primitive wing-coloration show such a well-defined design as 

 in Vanessidœ, the intra-marginal series of light spots being 

 absent on both] fore- and hindwings. This fact corresponds 

 with the character of the ornamentation of the pupal wing- 

 sheath, in which the homologues of the said spots are likewise 

 lacking, or at least are only very doubtfull}' marked {Papilio 

 machaon, Gonepteryx rhamni). 



In consequence of this deficiency the primitive pattern is 

 forcibly restricted to the ground-colour, but the presence of 

 this latter, in such a well-pronounced, characteristic way, is 

 none the less a remarkable feature. 



In Pieris brassicœ this primitive ground-colour is whitish, 

 but its optical aspect differs from the white of the imaginai 

 pattern. 



In the few stages of E. cardamines I succeeded in observing, 

 the wings, which had remained semi-transparent through the 

 whole period of hibernation, got white and opaque at the be- 

 ginning of spring, and then changed to a pink hue, which 

 first invaded the interveinal spaces, but shortly afterwards 

 coloured also the nervures, so that the whole wing became 



