IV] NEW-WORLD MIMICS 45 



groups of Swallow-tails in S. America, whereas in 

 Asia the Cosmodesmus division never provides mimics 

 for Pharmacophagus models (cf. Appendix II). 



In the second and smaller group of the Pharma- 

 cophagus Swallow-tails the general colour scheme is a 

 more or less dark metallic blue-green with a tendency 

 towards the obhteration of light markings. Some 

 idea of their appearance may be got from the figure of 

 the Central and N. American P. philenor on PI. XVI, 

 fig. 1. Though one or two unprotected PapiUos 

 in S. America fall more or less into this colour scheme, 

 the group, from the point of view of mimicry, is not 

 nearly so important as the red-spotted one. 



Nevertheless the blue-green Pharmacophagus group 

 as represented by P. philenor is supposed to play a con- 

 siderable part in mimicry in N. America. P. philenor 

 is found throughout the greater part of the Eastern 

 United States, stragghng up as far as the Canadian 

 border. On the west it is also found reaching up 

 to North California. Over considerable parts of its 

 range are three other Swallow-tails, belonging to 

 the unprotected Papilios, which are regarded by 

 Professor Poulton and others as mimics of philenor^. 

 One of these, P. troilus, is dark brown with a dusting 

 of blue scales over the hind wing (PI. XVI, fig. 2). 

 The sexes here are more or less alike. Troilus stretches 

 up into North-west Canada some way beyond the 

 limits reached by its model. P. cjlaucus is a black 

 and yellow Swallow-tail with two forms of female. 



1 Cf. Poulton, Darwin and the 'Origin; 1909, pp. 177-186. 



