BUTTERFLIES OF MONTANA. 



G9 



^>S- 55. Venation of 

 Br'inthis myrina. 



Genus BRENTHIS, Hubner. 

 Butterfly — Small or medium size; in form and color very much like 

 Argynnis. 



Egg — The eggs are subconical, almost 

 twice as high as wide, truncated at the top, 

 and marked with thirteen or fourteen raised 

 longitudinal ridges connected by a multi- 

 tude of small cross ridges. 



Larva — Smaller and not as dark in color 

 as the larva of Argynnis. They feed upon 

 violets. 



Chrysalis — It is pendant, about six-tenths 

 of an inch long, and having two rows of 

 sharp conical tubercles on the back. 

 GENUS BRENTHIS. 

 Key to Species. 



1. Basal part of wings not differing from 

 the rest, 2. 

 Basal part of wings black, 3. 



2. Under side of wings with silver spots; 

 ocellus at base of hind wings 



myrina 

 '3. Under side of wings without silver spots and ocellus; a purplish 

 ferrugenous color at the apex, bellona. 



Cinnamon brown at the apex of fore wings; hind wing crossed by 

 a yellow band formed of star-like spots; black ocellus at base of 

 wings, helena. 



THE SILVER BORDERED FRITILLARY. 



Brenthis myrina, Cramer. Figs. 55, 56. 

 Butterfly — The upper side of the wings is fulvous; the black mark- 

 ings are light; the borders heavy. The fore wings on the under side are 

 yellowish fulvous, ferruginous at the tip, with the marginal spots lightly 

 silvered. The hind wings are ferruginous, mottled with buff. The spots 

 are small and well silvered. Expanse male, 1.40 inches; female, 1.70 

 inches, 43 mm. 



Egg — The egg is conoidal, about one-third higher than wide, marked 

 by seventeen vertical ribs, between which are a number of delicate cross 

 ribs. It is pale greenish yellow in color. 



Caterpillar— In its final stage it is about seven-eighths of an inch long, 

 dark olive brown, marked with green; the segments being adorned with 

 fleshy tubercles armed with needle-shaped projections. 



Chrysalis — It is brownish yellow, spotted with dark brown spots, 

 those of the thoracic and first and second abdominal segments having 

 the luster of mother of pearl. 



Distribution — It has a wide range, extending from New England to 



