to limitations of the Milllerian Hypothesis of Mimicry. 107 



in other members of the same genus its appearance in any 

 one species might well be due to simple affinity with them 

 and not to mimicry at all. The fact that the model and 

 the mimic possessed ab initio certain superficial characters 

 in common would of itself render a mimetic approach the 

 more probable ; yet the occurrence of these similar mark- 

 ings would, in no sense, be due to mimicry, and no 

 argument for diaposematism could be founded upon them. 



The first point therefore to be investigated is the 

 occurrence of this red spotting in Heliconius. With the 

 accession of the splendid Godman and Salvin collection 

 the British Museum now possesses a very fine series of this 

 genus. A careful examination of this material, based on 

 Riffarth and Stichel's monograph of Heliconius in the 

 " Theirreich," shows that out of the 71 species recognised 

 by these authors no less than 35 * possess basal red spots 

 on the under-side of the hind-wings. Of the remaining 

 36 species about three-fourths have been drawn away in 

 mimicry of the great Mclin&a-Mechanitis association, and 

 the absence of red spots may perhaps be actually due to 

 this mimicry ; for I have been unable to find that any 

 genus of Ithomiinse or Danainge possesses this kind of 

 marking. The Heliconii in which the red spots are 

 present belong to various different types of coloration, 

 several of which do not appear to be mimicked by 

 Pierines, and in some of these the red spots are very 

 highly developed, more so than in any non-mimetic 

 American Pierines. Nor does there appear to be any 

 constant connection between general mimicry and the 

 development of the spots. For example, Pieris locusta % 

 roughly mimics H. cydno-galanthus, and the nearly allied 

 P. noctipennis $ mimics H. sapho-leucc (Dixey, " Nature," 

 Oct. 1907, p. 677); the under-side red spots of the two 

 Pieris are almost identical, yet those of the Heliconius 

 differ very much from them and from each other. 



Turning now to Pereute we find that the colour of the 

 under-side of the hind-wing may be generally described 

 as dark brown with a variable yellow costal streak, and 

 with, or without, two or three basal red spots. With 

 regard to the upper-side colouring the genus may be 



* It may be noted that the great majority of these species also 

 have a red streak along the base of the costa of the fore-wing on the 

 under-side, a character which I have failed to find in any American 

 Pierines. 



