SYNAPOSEMATIC GROUPS 345 



All of these, in common with numerous other species which 

 inhabit the same area, Ij^ve adopted the same characteristic 

 scheme of warning colouration, wherein the prevailing tints are 

 black and orange. 



In such a synaposematic group, or mimicry ring, it is usually 

 possible to distinguish between certain species which seem to 

 have led the way in the development of the warning colouration, 

 and others which seem to have followed their example. In 

 the particular case under notice the original " models " belong 

 to the group Ithomiinae, of which Tithorea harmonia (Fig. 176, A) 

 is a representative. These are probably the most distasteful 

 members of the combination to birds. They have been imitated 

 by Heliconinae, such as Heliconius ethilla (Fig. 176, B), Pierinae 

 ("whites"), such as Dismorphia praxinoe (Fig. 176, D), and 

 Hypsidae (a family of moths), as exemplified by Pericopis angulosa 

 (Fig. 176, E), all of which may be regarded as mimics of the 

 Ithomiinae. 



The case of the pierine mimics is particularly instructive, 

 and shows very clearly that these forms really imitate other 

 species, for the female is commonly a far more perfect mimic 

 than the male, which often departs little, if at all, from the typical 

 colouration of the group to which it belongs. Fig. 176, C repre- 

 sents a male pierine, Perrhybris (Mylothris) malenka, which is 

 at once recognizable from its colouration as a " white," although 

 even here, curiously enough, there is a faint trace of the warning 

 colouration on the under surface of the hind wings. 1 The 

 female of the same species has the warning colouration well 

 developed, as it is in both male and female of Dismorphia 

 praxinoe. 



So different are the males and females of some of these 

 mimicking species that it would be difficult to believe, were it not 

 for breeding experiments, that they are really specifically 

 identical. The explanation of the difference is doubtless to be 

 found in the fact that it is much more important, from the point 

 of view of the species, that the females, heavily laden with the 

 eggs upon which the existence of future generations depends, 

 should be able to warn off the birds, than that the males should 

 do so, for the latter, having once accomplished the fertilization 

 of the eggs, is of no further value to the race. 



1 Doubtless inherited incompletely from female ancestors, as in the case of the 

 vestigial nipples of man. 



