30 Canadian Record of Science. 



In Lycpena, or the " Blues," the females are generally 

 more heavily bordered with dark brown than the males, 

 and sometimes are almost entirely brown, witli a border 

 of orange spots. * 



Among the skippers the differences are generally well 

 marked in the Pamphilidi, in which the males are gene- 

 rally more tawny than the females, and frequently have a 

 peculiar discal dash on the front wings where the 

 androconia are placed, but are not well marked in the 

 other tribe, the Hesperidi, though in some genera the 

 male has a peculiar fold on the costal or front margin of 

 the fore wings in which the androconia are concealed. 

 But though I have not nearly exhausted the subject 

 of sexual dimorphism, I must hasten on to treat of the 

 more general subject of dimorphism and polymorphism 

 other than sexual. 



It is a very remarkable fact that certain species of 

 butterflies exist in two or more distinct forms which in 

 many cases have been described as distinct species. 



This kind of dimorphism may be partial or complete, that 

 is, it may exist in one sex or both. Further, it may occur 

 in part of a butterfly's habitat, but not in all parts. 

 Again, it may be seasonal or occur regardless of season, or 

 it may be partly seasonal and partly not. 



To take a few instances of partial dimorphism, one of 

 the most striking is the case of our common yellow swal- 

 lowtail, Papilio Turnus. 



In the north both sexes are yellow, but south of a line 

 which may be roughly described as starting at a point a 

 little south of New York and curving northwesterly to a 

 little north of the international boundary north of 

 Montana, a black form of female, to which the name 

 Glaucus was given, begins to take the place of the yellow 

 form and rapidly replaces it to total exclusion as we go 

 south to the Gulf States. 



Another somewhat similar case, but in the reverse sex, 



