8 MONTANA EXPERIMENT STATION BULLETIN 366 



two-thirds of the State, M. mexicanus was the dominant form. 

 In the southern half of this area Aulocara elliotti (big-headed 

 locust) occurred in considerable numbers, and M. packardi and 

 M. bivittatus to a less extent. Conditions in the north half of 

 this area were similar, but M. packardi was possibly more abun- 

 dant in many areas than A. elliotti. For the first time, at least 

 in many years, the eastern M. dijjerentialis (differential locust) 

 was a dominant species. In some of the irrigated sections of 

 Richland County the species was present in large numbers and 

 laid many eggs. 



No critical injuries to humans were reported as a result of 

 the 1937 campaign. Thirty-two domestic animals died as a result 

 of careless exposure of bait or bait materials. 



The 1938 season was characterized by a definite break in the 

 drought period, and both cultivated and wild vegetation grew 

 luxuriantly throughout practically all of the State. Hatching of 

 grasshoppers was from 4 to 6 weeks late, not being well under 

 way until after the first week in June. Small numbers con- 

 tinued to hatch throughout the season. Rankness of vegetation 

 doubtless contributed to this late and long-continued hatch. In 

 fact on ranches near Wilsall, in Park County, there was prac- 

 tically no hatch until the first cutting of alfalfa was removed. 

 The hatch became general on these fields as the soil warmed up. 



In the western third of the State there was again a great 

 variety of species, the most of the damage to crops being at- 

 tributed to Camnula pellucida, Melanoplus mexicanus, and M. 

 packardi. In the central third of the State M. bivittatus, M. 

 packardi, C. pellucida, and A. elliotti, were dominant. In the 

 eastern third M. mexicanus was dominant, with local concentra- 

 tions of M. bivittatus, M. jemur-rubrum, and M. dijjerentialis 

 in injurious numbers up the Yellowstone Valley into Custer 

 County. 



The increase of cool damp weather over the State was 

 doubtless an important factor in reducing grasshopper popula- 

 tions in 1938. Locally, fungus was efficient in keeping numbers 

 down, and, although Sarcophagid flies were not observed to be 

 present in excessive numbers, there was a constant reduction in 

 grasshopper numbers due to parasitism caused by maggots. It is 



