on Milllerian Mimicry and Diaposematism. 577 



has taken place as between these groups, I think that 

 those naturalists who are well acquainted with the species 

 concerned will regard his conclusion as a ixductio ad 

 ahsurdum. 



Why do hoth sexes of Archouias (Euterpe) tereas mimic 

 only the females q/'Papilio zacynthus ? 



In this section of his paper Mr. Marshall makes the 

 curious statement that "not a single one of the American 

 Pierines has developed any metallic colours" (p. 111). 

 By " metallic colours " he shows in the same passage that 

 he means an iridescence or glow such as- may be seen 

 in certain African species of Teracolns, for example in 

 T. regina, where it exists in a highly-developed condition. 

 Has Mr. Marshall ever looked at Dismoiyhia tcresa ? 

 Or at the male of Megaiiostoma eurydicc, or of Colias leslia 

 and C. vautieri ? Or at a fine male specimen of Phoehis 

 argante ? Even in the Pierine genus at present in 

 question, it is by no means rare for a well-preserved 

 example of Euterpe approximata or E. critias to exhibit 

 a purple gloss on the hind- wing, a gloss which, though 

 comparatively undeveloped, recalls that of many Papilios. 

 The fore-wings of E. antodyca $ and E. stoainsonii $ often 

 show a similar bloom. Then as to African forms, has Mr. 

 Marshall forgotten Colias electra, of which he must have 

 seen innumerable specimens ? There can I think be no 

 doubt that there is nothing in the Pierine constitution to 

 prevent the development of " metallic " colouring, should 

 the opportunity and need for such development arise in 

 the history of a species. In reference to F. Muller's 

 statement that although in his experience Euterpe tereas 

 was common, and Papilio nephalion rare, the latter must 

 be regarded as the model rather than the former, Mr. 

 Marshall seems to be quite alive to the fact that if this 

 case of mimicry is, as he says, " in every way consistent 

 with the interpretation of a simple Miillerian approach," 

 it remains an instance that primd facie requires a good 

 deal of reconciling with his view as to the improbability 

 of Miillerian appioach even when the numbers are equal, 

 and much more when the numbers of the " model " are 

 inferior. I myself should of course agree with F. Miiller 

 that the Pierine has adopted most of its peculiar aspect 

 in imitation of the Papilio; but I should not consider that 



