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many of the wild birds have been Icnown to eat of and be killed 

 by it. Enough birds have been killed on one small garden to 

 have destroyed all of the locusts found upon the same tract ol 

 land in several days' time. Arsenic-sprays might be all right 

 in a well-fenced district, but could most certainly not be recom- 

 mended for "open fields and camp where all kinds of stock run 

 at large. 



The «contact» preparations are usually too expensive in their 

 application when used against destructive locusts to be of eco- 

 nomic value. Some of these preparations in order to kill the 

 insects must be made so strong as also to kill vegetation. Of 

 course where all the appliances for their use are at hand, and 

 the insects are condensed into very small space the result 

 often proves quite satisfactory. 



From the various hints thrown out in this chapter, as well as 

 in connection with life-history and habits, the reader will gather 

 sufficient information to satisf}' himself that there are man}' 

 ways of killing locusts. 



Experiments which were made at Careara ñá, show that 

 under ordinarily favorable conditions the saltonas in their 

 fourth and fifth stages can be caught b}' driving into trenches 

 for, not to exceed, seven paper dollars per ton; and with the Car- 

 carañá machine for about one and a half dollars per the thou- 

 sand kilos. Of course these figures represent cases where ev- 

 erything was done in accordance with the insect's habits, and 

 where the work progressed smoothly under proper instructions 

 and supervision. The insects Avere also present in very large 

 numbers, but were not more numerous than is often the case. 



Driving locusts. 



One very important method of destro3Íng these insects is b}' 

 driving them together and into some ditch or pit previously 

 prepared for the purpose. This method is applicable in many 

 places; as for example, in the garden, the field, on roads, the 

 open camp, and even in groves of trees where machines cannot 

 be used. Besides, it is a very inexpensive way of getting rid 

 of small mangas of the insects, and can be done by children and 

 women while the men are engag-ed in other labor. 



It should be borne in mind, however, that there is a right way 



