Erratum (to be bound facing page 277). 



Owing to an accident some of the folios of the article, pp. 277-279, 

 have been misplaced. This has entirely altered the sense and mean- 

 ing of what was written, and has carried over to J'ajiilio asterias and P. 

 phili'vor remarks made about /'. wacliaon. At the bottom of p. 277 

 (following " the older wood "), and throughout p. 278, the paragraphs 

 should read as follows : — 



Amongst the young stems of Lonicera I found 20, the 14 green 

 amongst the leaves or upon the young wood, with two exceptions, 

 whilst the six blacks were all upon the lower stems of old wood. In 

 addition to them I found a few pupsE on London Pride, perennial 

 phloxes, etc. Twenty-four larvse, which I removed indoors and fed upon 

 Skimmia in a large breeding-cage of perforated zinc and wood, all changed 

 to pupfe of the brown variety. These results only confirm my observa- 

 tions of previous years, and it appears to me that the presence of the 

 more common green variety is almost always coincident with pupation 

 amongst green leaves. I think it is certain that it is not due to exposure 

 to more light, for all the pupfe which I found in the full sunlight on 

 the white wood of the butterliy-house (some of these were even on the 

 top) were of the brown kind. To turn to another matter, viz., the 

 wish to find out, if possible, when the colour of the pupa is determined. 



I removed, on August 6th, five larva which had already spun up 

 for pupation upon the lowest black stems, and pinned them up with 

 as little of their former surroundings as possible amongst the topmost 

 green shoots ; all five, however, changed into brown pup^e. At the 

 same time I removed seven of the larvae spun up amongst the green 

 shoots, and pinned them to the black stems at the bottom of the shrubs, 

 taking care either to remove the larva? altogether from the brown stems 

 to which they were attached, or to change the colour of the latter by 

 smearing them with soot, etc. All these, however, remained green, as 

 did two on stems which I placed indoors in a dark box. These larvae 

 were removed from their natural surroundings from two to five days 

 before pupation, indeed, as soon as they were securely fixed up, a fact 

 which, I think, proves that whatever determines the colour of the 

 resultant pupa is an aftair of some time previous to the change itself. 

 The above observations, in addition to similar ones of previous years, 

 incline me to think that the colour dimorphism of P. viachaon is 

 specially of a mechanical nature, though, of course, the results are 

 not conclusive. 



With a view to obtaining confirmatory evidence of my results with 

 P. viachaon, I bred this summer some 40 specimens each of Papilio 

 asterias and P. philenor, two North American species with dimorphic 

 pupae. P. asterias, as I daresay most readers of this article know, is a 

 near relation of P. machaon, the ovum and larva are very similar, 

 though the female imago resembles P. troilus more closely. P. philenor 

 is a subtropical butterfly, and more nearly allied to the Ornithoptera. 

 My results with these were, however, less conclusive. I found both 

 the green and red-brown forms of the pupa of P. philenor upon the 

 white wood of the bntterfly-house, though the pupa; on the young 

 stems of Lonicera were of the green variety, and those on tree-stems, 

 etc., away from green leaves were red-brown. With regard to P. 

 asterias I found also that the pupa; found upon the wood of the butter- 

 fly-house were indifferently green or brown, those on its foodplant, 

 fennel, were green. 



