S THE ORTHOPTERA OF MINNESOTA. 



the wind was quite changeable, and the insects seemed to 

 beat about, sometimes going northwest, and at other times 

 retracing their course, flying southeast and south. Towards 

 the middle of August the w^inds became more constant from 

 the northwest, and the direction of flight more constant 

 south and southeast, until all the healthy locusts had left. 



Since that time portions of the state were twice invaded 

 by this species of locust, viz., the Migratory Locust {Mela- 

 noplus spretus). Thehistory of both invasionshas been given 

 in former bulletins, and only the essential points will be re- 

 peated. It seems that during the summer of 1885 a few 

 struggling specimens of this migratory locust reached Otter 

 Tail County (PerhamV Their offspring were seen again in 

 1886, when they caused but very slight damage; in 1887 

 they had already increased to such an extent that the crops 

 of 3,000 acres were swept away. In 1888 people became 

 alarmed and appealed to the governor, A. R. McGill, for 

 assistance. Many machines, hopper-dozers, were used to 

 kill the enemy, and with good results. Nearly 200 of such 

 machines were at work, each having a superficial surface of 

 over 4,800 square inches. The men operating them were 

 requested to keep a measurement in inches of locusts swept 

 off" the pans; they reported from two to twenty-one inches 

 daily, which would make about 5,000 bushels of dead lo- 

 custs, and as these were quite small at the time, not much 

 larger than a grain of oats, it takes an immense number to 

 fill a bushel measure. At Perham another method was 

 adopted by the citizens, who offered a bounty of one dollar 

 per bushel. The quantity of locusts caught by the "balloon 

 hopper-catcher," the invention of Mr. A. Maguire, was 

 astonishing, and 14,643 bushels were caught and paid for 

 between the first and the twent^^-seventh of July. As it 

 required about 7,000 locusts to fill a bushel measure, 

 102,438,000 were destroyed by this means alone. All told 

 about 35,000 bushels of locusts were killed in Otter Tail 

 county before they had caused very great loss. 



