31 



had seen the typical forms attack and persistently follow 

 these variations, just as was well known was the case with 

 birds who persecuted any of their own species which were 

 strikingly aberrant in colour. He also stated that valesina 

 was peculiar in its habits ; it was local, and much shier and 

 more retiring than the ordinary female form, with which it 

 did not associate. 



Mr. Robinson asked what was the condition of the scales 

 on these patches, as they appeared to him to be more or 

 less transparent or absent. Mr. Frohawk stated that he 

 had examined the scales under a microscope, and had found 

 that they were present, but were without the ordinary 

 pigment. Mr. Tutt then remarked that this statement 

 practically gave away the whole theory propounded by Mr. 

 South (and suggested by Mr. Frohawk), viz. that the marks 

 were simply ancestral characters ; for the allied species 

 which had been mentioned, and in which pale marks 

 appeared towards the costa, as pointed out by Mr. South, 

 and which he considered were parallel to the pale patches 

 exhibited by the male A. paphia to which the discussion 

 referred, had these pale patches fully pigmented. He 

 further considered that the irregularity in size and shape, 

 the variation in position, and the fact that the peculiarity 

 was sometimes extended to a whole or to a large portion of 

 a wing, militated against the idea ; while to say that the 

 patches were reversions to ancestral characters was no 

 explanation of the cause of the patches, which was evidently 

 what one wished to arrive at. In every effect there was a 

 cause, and the question was, what caused certain portions 

 of the wing of certain Argynnids to develop these abnormal 

 pale patches ? Mr. Frohawk's statement that there was no 

 pigment in the scales on these patches made the matter a 

 purely physiological one, for it showed that the ordinary 

 material — pigment factor, as Dr. Riding termed it — has 

 never been deposited in the scales. What caused the 

 failure of this deposit ? is the next question. It could not 

 be that at some previous stage the ancestral form had had 

 no pigment in the scales in certain portions of the wings, 

 nor did Mr. South suggest this ; but in the cases which Mr. 

 South relied upon — the pale patches in var. valezina and 

 other species — the scales forming these pale patches were 

 thoroughly pigmented, the mature pigment-factor only pro- 

 ducing a paler colour than the normal fulvous colour "of the 

 males of such Fritillaries as A. paphia. He considered that 

 these pale patches were analogous with similar pale patches 



