GENUS COLIAS 117 



The food-plant of the entire genus is trifohuin of various spe- 

 cies, and also in part, legumes. Possibly, also, other plants at 

 present unknown as such. In a general way, alfalfa is now the 

 usual food-plant ; and it is also the chief blossom upon which the 

 common species Eurytheme and Keevvaydin butterflies feed. 



76. Colias Eurytheme. 



Plate X ; Figures 76, a, b, bb, c. 



Fig. 76, Male, Tehacliapi Mountains, Aug. 10, 1876; 

 Author. 



a, Male, underside. Highlands, Cal., Oct. 4, 1897; 



Author. 



b, Female, Greenhorn Mountains, Cal., June, 1888; 



Author. 

 bb, Female, white, dimorphic, S. Cal., July, 1889; 

 Author. 



c, Female, white, dimorphic, underside. S. Cal., July, 



1900; Author. 



Eurytheme is considered the type of the orange Colias of the 

 West Coast, as it was noticed and named twenty-six years before 

 the so-called seasonal varieties Ariadne and Keewaydin were 

 found. This, however, is an error that has crept in, for Keeway- 

 din is the stem of the species, and Ariadne and Eurytheme arc the 

 varieties. Keewaydin can be taken in any month of the year, in 

 some place or other, but Eurytheme and Ariadne are limited in 

 season. 



The dimorphic female. Fig. bb. has never been named ; it is 

 merely called Alb. or Alba. It is now quite common, though 

 twenty-five years ago it was a great rarity, and it was accounted 

 a feat to secure one of them, and if the present rate of increase of 

 the blonde form shall go on, in a few hundred years the normal 

 orange-colored female will be e.xtinct and unknown. At present 

 half-whites are abundant : they vary from those having a mere 

 whitening dust on the apices to the full-colored white specimen 

 shown as Figures bb, c. 



77. Colias Ariadne. 



Plate X ; Figures "]"], a, aa, b, c, d, e. 



Fig. JJ, Male, plains near San Bernardino, Jan. 14, 1900; 

 Author. 



