THE ORTHOPTERA OF MINNESOTA. 9 



In 1889 about the same area was infested, but as mone\' 

 had been appropriated by the legislature to combat the in- 

 sects before they were hatched, no loss was caused by them. 

 Instead of depending alone upon "hopper-dozers" and 

 "balloon-catchers," the fields that were found to be filled 

 with eggs were deeply plowed. Other remedies were also 

 applied, as will be mentioned in the proper place. In all 

 6,361.59 acres were plowed, and with most excellent results. 



In 1891 another invasion, on a smaller scale, took place. 

 This time parts of the Red River Valley were invaded, not 

 alone b}^ the Rock\' Mountain Locust, but also by two other 

 species of migratorj- kinds, the Lesser Migrator\' Locust 

 [Melanoplus atlanis), and the Pellucid Locust (Camnula 

 pellucida). By the immediate use of hopper-dozers and other 

 means farmers succeeded in preventing serious loss, and 

 being forewarned they plowed ever\' field that was even 

 suspected of containing eggs, and on this account no locusts 

 appeared in 1892. 



Since that time (1891) the state has been free of this 

 dreaded insect, but, as may be judged Irom the history of 

 invasions just given, our farmers can not expect that these 

 migratory locusts will not again appear in the future. In 

 fact, our state, or rather portions of our state, are unconi- 

 fortabU' near the permanent breeding grounds of this locust, 

 which extend chiefl\' along the eastern Rocky Mountain 

 range, from longitude 102° to 140° west of Greenwich, and 

 from latitude 53° to 40° north, comprising most of the 

 levels below an altitude of 6,000 feet and above 3,000 feet. 

 In man\^ portions of this area they breed ever\^ 3'ear, and 

 lead an essentially migratory existence. This permanent 

 breeding area gradually shades into a sub-permanent 

 region, in which locusts breed more or less frequently, and 

 which is liable to be invaded at any time, or rather when- 

 ever the insects become very numerous in their true breeding 

 grounds. This region includes a large portion of British 

 America, nearly all of the Dakotas, Western Nebraska, 



