26 Canadian Record of Science. 



Argynnis ISTokomis is a splendid species, in which the 

 male is of a fiery fulvous, while the female is of a dark 

 brown tone, and Argynnis Leto is a similar though less 

 marked example in the same class. But the most striking 

 case in this genus is that of Argynnis Diana, the most 

 superb species of the genus. In this the male, while 

 fairly preserving the usual colors of the genus, departs 

 widely from the normal type of ornamentation, as instead 

 of the ground color being fulvous, marked with bars and 

 spots of black, it is for two-thirds of the distance from the 

 base of a dark brown color, with a brig-ht tawny border, 

 but the female not only departs widely from the usual 

 type of ornamentation, but also loses every trace of 

 tawny or fulvous coloring, becoming a dark blue butterfly 

 with a striking resemblance to the genus Limenitis. 



This is an example of the fact that where there is 

 marked dimorphism between the sexes it is almost 

 invariably the female which departs from the usual type, 

 but whether this is to be accounted for by the general 

 desire of that sex for striking and varied costumes, I 

 am unable to say. 



The genus Colias, one of the most puzzling and, there- 

 fore, most interesting, of genera, furnishes some striking 

 cases of sexual dimorphism. 



This genus is composed of the so-called Sulphur Butter- 

 flies, the yellow or orange butterflies which are found 

 everywhere, flitting about the clover fields especially, and 

 which Dr. Scudder thinks were probably the first to 

 be called butterflies, as the yellow Eanunculus is called 

 the buttercup. The most striking case of sexual dimor- 

 phism in this genus is Colias Eurydice, which some 

 authors separate from that genus under the generic name 

 Meganostoma. 



It is a most beautiful species in the male sex, but the 

 female is of a uniform pale sulphur yellow, only resem- 

 bling the male in the shape of the wings and in the discal 

 spot of the primaries. 



