Butterflies of the Subfamily Pieriiiie. 427 



emplialically that gidica is not the wet-season fonii of 

 ahyssinica.' " 



The above statement does f^'ive the impression, whether 

 intended or not, that in 1S98 I flatly contradicted the state- 

 ment made by myself in 1894; but Prof. Aurivillius, with 

 both papers before him, is perfectly well aware that the 

 B. gidica of the first and second papers were entirely different 

 species or forms. 



In 1894 we knew B. gidica from description only, and it 

 was supposed by all lepidopterists to be identical with the 

 B. Westicoodi of Wallen<^ren ; but Godart^s type came into 

 the possession of, I believe, the Edinburgh Museum, was 

 brought to the British Museum for comparison, and thus the 

 fact that it was quite distinct from ^. Westwoodi (^=B. gidica 

 auct. plur.) was made evident. 



In 1898, in the very paper to which Prof. Aurivillius 

 refers as evidence of the instability of my emphatic utterances, 

 I described the true B. gidica as explanation of the very 

 sentence quoted, only part of which, moreover, was quoted, 

 since to quote the whole would have made the misrepresen- 

 tation of my assumed change of front evident : what I added 

 is, " Furthermore, there are two South-African species of the 

 group, easily separated by anyone who has an eye for form 

 and pattern " ; and I then proceeded to describe the differences 

 between the typical B. gidica and the form previously 

 regarded as that species by lepidopterists generally. 



But, to make the point still more unmistakable, I in the 

 same paper described the seasonal forms both of B. ahyssinica 

 and B. Westwoodi, showing that they are not, as I formerly 

 supposed, mere seasonal phases of one species, but that the 

 wet phase of each form is well marked, and indicates at least 

 the local distinctness of the southern and northern represen- 

 tatives of this type. 



Now, to examine Prof. Aurivillius's statement in detail. 

 It is not very remarkable that dry and wet phases should 

 both occur during the dry season. I have repeatedly shown 

 that, although the dry phase of a species is prevalent in the 

 dry season, examples of the wet phase are frequently present. 

 We do not know, and can only surmise, the cause of this fact : 

 it is possible that the position of a chrysalis near to or far 

 from the earth may have some effect in determining the 

 character of tlie developing butterfly ; in heavy dews it is 

 conceivable that the chrysalis near the surface of the earth 

 might be more affected by the moisture than if situated at 

 some height above the ground. 



Again^ I have shown that in very dry countries a species 



