Introduction. 



The present bulletin is the result of eight years of collecting and 

 tal)ulating material. My first butterflies captured in the state were taken 

 at Miles City in the east and Mount L,o Lo in the west during a recreation 

 trip in August, 1892. In 1897 1 came to the state to live. Every summer 

 since then to the present time has been spent in the field, and the ac- 

 cumulated insects have been arranged at the University of Montana, 

 where they have been worked over at leisure moments. 



In the fall of 1900 Miss Frances Inez Maley was given the task of 

 spreading, arranging and labeling the material, identifying it so far as 

 possible with the specimens and literature at command. A large portion 

 of her time for that school year was devoted to the work. The collection 

 of more than a thousand specimens was spread and arranged in Com- 

 stock cases. A large number of the photographs were taken at that time, 

 others later. Many of the keys and descriptions were prepared by her, 

 and the results of her careful and painstaking labor were submitted to the 

 faculty as her graduating thesis for the degree B. A. in June, 1901. 



As it was impossible then to correct and verify as must necessarily 

 be done before printing, it was decided to test the keys and make further 

 addition to the list by including references to all the collections avail- 

 able in the state. For several summers the keys have been in the hands 

 cf many persons both at the University in regular work and at the Uni- 

 versity of Montana Biological Station at Flathead lake. In this way many 

 errors have been avoided, and the keys have been found to be serviceable 

 in the hands of beginners. Moreover, by the examniation of other collec- 

 tions many additions were made, necessitating changes in the keys and 

 in the text. Many of the discriptions were rewritten. 



To avoid confusion it was decided to follow the nomenclature used 

 by Dyar and others in Bulletin 52, United States National Museum. In 

 this bulletin many species recorded in other publications are reduced to 

 synonyms or varieties of other species. After examining so many hun- 

 dreds of specimens from various parts of the state, at different altitudes, 

 I feel convinced that the list can be reduced still further without detri- 

 ment, and without sacrificing. To cite a single illustration. The Wiley 

 collection has specimens of Argy nn is from Miles City, collected in 1893, 

 and identified by Edwards as A. edwardsi. Specimens from Miles City 

 sent by myself to Edwards in 1892 were labeled A. nevadensis. When 

 placed side by side they look exactly alike, and are undoubtedly of the 

 same species. 



Owing to the varying conditions as to heat and cold, moisture and 

 sunshine, which prevail in the state, many species are subject to great 

 variation. This makes identification oftentimes difficult, and we have 



