MONTANA EXPERIMENT STATION. 233 



INJURY NOT CAUSED BY THE ROCKY MOUNTAIN 



LOCUST. 



Many persons have supposed the "ohl-fashioned" or Rocky 

 IMountain Migratory Locust to be responsible for the losses in Mon- 

 tana. Our investigations of the subject, however, show that no one 

 species is alone the cause of the loss and the above species {Melan- 

 oplus spretus Uhler) if present in the state at all is very rare. Dur- 

 ing the five summers that I have been collecting in all parts of Mon- 

 tana I have not captured a single example of this interesting species. 

 Moreover, I learn by letter from Prof. Gillette of Colorado that he 

 has had a similar experience, having been unable to find any speci- 

 mens during a longei period in his state. 



In our various trips into the worst afifected regions we found 

 a fairly uniform state of affairs throughout. On the range two or 

 three species, taken together, constitute a large proportion of the 

 total number, though in restricted localities one or another species 

 besides these was more abundant. The three most common species 

 on the range were the Big-headed locust, {Aulocara elliotti), the 

 Lesser Migratory locust {Melanoplus atlanis) and the Yellow- 

 w'inged locust (Camnula pellucida). In point of abundance the Big- 

 headed grasshopper was the leading species of the three. The Less- 

 er Migratory Locust was second in importance. It prefers the dryer 

 uplands to the irrigated valleys, but in many cases it was found in 

 great abundance in grain fields, particularly on the benches and in 

 non-irrigated fields. 



The Yellow- winged Locust is more local in its distribution, 

 often occurring in immense numbers in restricted localities and at 

 times becoming very injurious to grasses and grains. 



We found the two-striped locusts to be common in practically 

 all the cultivated fields that were injured by grasshoppers. This 

 species was particularly injurious to alfalfa, the succulent stems and 

 leaves of this plant apparently suiting its taste. 



LIFE HISTORY. 



All our particularly injurious species are alike in the main fea- 

 tures of their life history. The winter is passed in the tgg stage in 



