ART. XXIII-ON THE LEPIDOPTERA COLLECTED BY DR. 

 ELLIOTT COUES, U. S. A., IiN MONTANA, DURING 1874.* 



By W. H. Edwards. 



The butterflies were few in nurnber, but embrace some interesting 

 species, and at least two tbat are new. They were taken at various 

 points on the forty- ninth parallel, in Montana, between 2Gth July and 

 2Gth August, a season of the year not favorable to collecting these in- 

 sects, being too late for the early broods and too early for the autumnal. 



Px\PILIONID^. 



1. Fieris protodice^ Boisduval. 



2. Pier is occidentalis, Eeakirt. 



A few specimens were taken early iu August at the point of crossing 

 Milk Eiver and beyond. P. protodice ranges over the continent from 

 New York to California, and on the western coast is found in British 

 Columbia. It is, however, much more, abundant to the eastward, and 

 iu the Ohio Valley is extremely common in the months of August and 

 September. So far as appears, it is single-brooded, and passes the win- 

 ter in chrysalis. The larvae feed upon cabbage, horse-radish, and allied 

 plants. 



P. occidentalis is a Western species, not known this side of the Rocky 

 Mountains, but ranging from Colorado to the Pacific. It may be dis- 

 tinguished from protodice by the more rounded, hind margins of prima- 

 ries, and by the arrangement of the curved band of black patches on 

 the discs of the same wings, there being a patch near the inner margin 

 which completes the band. The under side is paler and more yellow - 

 dusted than is the«other species. 



3. Colias keewaijdin, Edwards. 



This species occupies the same territory with the larger and deeper- 

 colored orange species, G. eurl/theme, Boisduval, and may perhaps yet 

 prove by breeding from the egg to be a variety of that ; but, till so proved^ 

 it is sufficiently distinct to warrant its being regarded as a true species. 

 These orange Coliades are found from Illinois to the Pacific and as far 

 south as Arizona. Their larvae feed on buffalo-grass and species of 

 clover, and that of Colias eurytheme so closely resembles the larva of 0. 

 pliilodice, the common species of the Eastern States, that it can scarcely 

 be distinguished from it. 



[*See note, p. 481, anted. — Ed.] 



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