THE ORTHOPTERA OP MINNESOTA. 31 



hind legs ; it will stretch them out, but they soon become 

 useless both for walking and kicking. In some localities, 

 and on days with little wind or dust, these simple contriv- 

 ances are very useful. 



The use of kerosene oil has an additional advantage: it 

 leaves behind in the field a very strong odor which is dis- 

 liked by the insects, and they almost stop feeding, moving 

 about to escape it. Of course one thing should be remem- 

 bered, namely that this oil is just as deadly to plants as to 

 locusts, hence great care should be used to prevent its 

 spilling. In less level regions the rim of the pan should be 

 made wider, and partitions should also be added, as shown 

 in one of the above illustrations (Fig. 8). Smetimes in- 

 stead of pulling the pan it can be left stationary, and the 

 insects can be driven into it. This has frequently been done 

 in fields containing numerous stumps, and with good results. 

 In places where the machines can not be used on ac- 

 count of the rough, uneven, and too sloping condition of 

 the ground, and when cattle and chickens can be kept 

 away, there is no better way of destroying large numbers 

 of the locusts than by use of the poisoned baits already 

 mentioned. There are many other machines known that 

 can catch large numbers of locusts, but for our state, level 

 in most parts likely to be invaded bj^ such insects, the hop- 

 per-dozers described above are the best, and by all means the 

 cheapest machines known. 



How many locusts are really killed by a hopper-dozer is 

 difficult to say, as nine out of the ten that jump into it 

 jump out again, only to die afterwards in the field. But if 

 only five or six bushels of the still small locusts are scraped 

 off the "dozer" during a day's labor, this would mean 

 fifty or sixty bushels killed hj a single machine. This is by 

 no means an exaggerated estimate, but if only ten per cent 

 of these numbers were killed it would well pay for the work. 

 But after all, no matter how useful hopper-dozers may 

 be against locusts and other insects feeding upon grass, 



