Vol. XXlv] ENTOMOLOGICAL NEWS. 



mens in a thicket of willow near Phoenix, Arizona, and had 

 no difficulty in capturing a fine series. Their flight was slow 

 and unconcerned not at all like the nervous action of its 

 white-barred cousins. Other specimens taken on the open 

 mesa several miles from the river were not so fresh and evi- 

 dently had strayed from their breeding grounds. The flight of 

 these was so like strigosa that I at first mistook them for their 

 models and allowed a number of them to escape. 



The Batesian Theory as applied to these species. 



If we could look back into the dim past ages, we might first 

 obtain a glimpse of North America with the white-barred 

 Limenitis in evidence. The next glimpse might show a change 

 in the climate about the Behring Sea which enables the pro- 

 genitor of plexippus to find its way across from Asia, where 

 the Danaidas are very much in evidence. This insect, finding 

 the climate and food of the fairly cool temperate region to its 

 taste, increases and multiplies to its present magnificent 

 form, (i) 



Strigosa may have drifted across at the same period as 

 plexippus, or maybe at a later period. It is remarkably like 

 certain of the Asiatic Danaidas, and probably has changed but 

 little. It found its way down the Pacific Coast and drifted 

 eastward over the hot, dry Southwest. When it reached the 

 humid region of the Southeast it became darker and richer in 

 color. 



What happened to our native Limenitis from this time on? 

 We have astyanax and various forms of white-barred Limeni- 

 tis, the prevailing colors of which are blue and black. We have, 

 also, three well-defined species entirely different in general 

 appearance from the others in that the prevailing color is rich 

 brown. Each of these three species is a remarkably close 

 mimic of the particular species of Danaida prevailing in its 

 territory. 



Who can doubt that we have here a clear-cut case of imi- 

 tation by selection? We cannot reasonably conceive that these 

 are all accidental cases of similarity. One such instance might 

 be imagined, but not three. 



