Dimorphism and Polyvior'phism in Butterfiies. 33 



Colorado last summer to work out on the spot the life 

 history of these most interesting forms. 



So far I have spoken only of dimorphism, but polymor- 

 phism also exists among our North American butterflies. 



The most striking instance so far known among butter- 

 flies occurring commonly in Eastern Canada is the case 

 of the beautiful little blue butterfly which may frequently 

 be seen in its favourite haunts early in May. Dr. Scudder 

 calls it the Spring Azure and its scientific name is Lycsena 

 Pseudargiolus. 



This species occurs in many forms, most of which have 

 been regarded as distinct species. In the north there 

 first appears the variety Lucia with an occasional Violacea 

 and sometimes an intermediate form which Mr. Edwards 

 named Marginata. Then in the summer there is the 

 form iSTeglecta. To the South, say in A^irginia, the forms 

 Lucia and Marginata do not occur, Violacea being the 

 regular earliest Spring form, but it has a dimorphic black 

 male to which reference has already been made, and 

 there is an additional and later Spring form, the largest 

 in the series and the one first described under the name 

 Pseudargiolus, while the later broods are few in numbers 

 and of the form Neglecta. 



In Arizona another variety occurs which Mr. Edwards 

 calls Cinerea, and there is also the Pacific Coast form 

 Piasus, with its variety, Echo, which occurs in California 

 and Arizona. 



A wonderful example of polymorphism is the case of 

 Colias Eurytheme the bright orange butterfly of the West, 

 though on two occasions single individuals have been 

 taken in this Province. 



Its typical form is of fiery orange with a heavy black 

 border, but there are also albino females ; then it runs 

 throueii various degrees of less orange until we get the 

 winter form Ariadne, small and with hardly any orange 

 at all, and then there is the form which Mr. Edwards named 

 3 



