PROTECTIVE RESEMBLANCE, WITH EXAMPLES 85 



the food plant of this butterfly appears, it is reasonably certain 

 both plant and insect will be found associated. 



For instance, the range of Arabis lyrafa, according to Britten 

 and Brown, is found to extend from Ontario to Virginia and 

 Kentucky, west to Manitoba and ISIissouri. It ascends to 

 twenty-five thousand feet in Virginia, and occurs on rocky 

 and sandy places. Now let us examine the range of the orange- 

 tip butterfly under consideration, and we find in Holland's 

 "Butterfly Book" that it ranges from New England to Texas, 

 but it is not found, so far as is known, in the regions of the 

 Rocky Mountains and on the Pacific Coast. Where this Httle 

 butterfly occurs, it is likely to be quite local. I have only 

 found it in the sand dune region skirting the border of Lake 

 Michigan, which is particularly rich in objects of zoological 

 interest. I have been told by John B. Smith that this but- 

 terfly was very local in its distribution in New Jersey. It is 

 single brooded in the northern states and I found it mating at 

 Dune Park, Indiana, in May. In North Carolina, Holland 

 found that it was double brooded, judging this to be the case 

 because he found it late in autumn. 



There are numerous species of the orange-tips of the genus 

 Anthocharis (Euchloe of some authors) in North America. 

 They are all small white butterflies, having the apical region 

 of the primaries spotted or banded with yellowish orange or 

 crimson. On the underside of the wings they are usually 

 more or less protectively mottled, as in the species genutia 

 that I have described above, each possessing yellowish green 

 spots or striae. The orange coloring of the apex of the fore- 

 wings is confined to the male in some species, and this patch of 

 coloring must be considered as of entirely different significance, 

 biologically, from that on the underside of the ^"ings. The 

 orange coloring is, perhaps, a distinguishing sexual mark belong- 

 ing to the epigamic colors classified by Poulton. 



Darwin ^ cited the case of the orange-tipped butterflies in 

 support of his theory of sexual selection. He says: "The 

 same reason which compels us to believe that the lower surfaces 

 have been colored for the sake of protection leads us to deny 

 that the wings have been tipped with bright orange for the 

 *" Descent of Man," p. 313. 



