BUTTERFLIES OF MONTANA. 79 



THE PEARL CRESCENT. 

 Phyciodes tharos, Drury. Fig. 64. 



Fig. 64. Phyciodes tharos, slightly reduced. 



Butterfly Expanse, male, 1.25 inches, 32 mm.; female, 1.65 inches, 

 41 mm. Upper surface reddish fulvous marked with black; two rows 

 of more or less coalescing circles near the base of the wing, the first 

 of two circles, the second of four, and an ellipsoid at the end of the cell; 

 a patch of black beyond the cell on the costa and one on the hind margin, 

 sometimes the two being connected by a dentate line. The outer border 

 is broad, black, and through it runs a crenated line' with a yellowish or 

 fulvous lunule in the middle, in some examples distinct, in others con- 

 nected with the central color; black dot near the posterior angle. 



Hind wings similar to front wings, the median black band narrower; 

 both light bands are fulvous, and the outer contains a row of black spots. 



The under side of fore wings yellowish fulvous, with yellow spots 

 and four black patches, two on the costa before the apex, one at the 

 posterior angle, and one on the hind margin. 



The under side of hind wings pale buff washed with umber-brown, 

 the basal half with more or less complete bands of pale spots edged with 

 brown; the row of black spots same as above; a sub-marginal row of 

 lunules, the middle large, silvery, the others more or less obscure. The 

 terminal, costal, and middle brown patches are present in some examples, 

 the wing being well suffused with brown. 



Early Stages The egg is light greenish yellow. The caterpillar, 

 which feeds upon various species of aster and allied compositae, is dark 

 brown after the third moult, its back dotted with yellowish and adorned 

 with short black bristly spines, which are yellow at the base. The 

 chrysalis is grayish white, mottled with dark spots and lines. 



Distribution This is one of the many dimorphic species. It ranges 

 from southern Labrador to Florida, in fact all over North America, north of 

 Texas and south of the region of Hudson Bay, except the Pacific coast of 

 California. Found in Montana at Missoula, Fish Creek, Ruby Mountain, 

 Crow Creek. Brandegee has it in his collection from Gold Creek. Wiley 

 collected it at Miles City. It is abundant around the Biological laboratory 

 at Bigfork. It is abundant in the Bear Paw Mountains, according to 

 Coubeaux. Dr. Elliott Coues collected it at Milk River July 25, 1874, called 

 by Edwards Marcia, now recognized as a synonym for tharos. 



