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JOURNAL OF ECONOMIC ENTOMOLOGY 



[Vol. 8 



In the sugar beet curly-leaf " studies the actual number of leaf 

 hoppers per beet was found to be closely proportional to the damage 

 done under similar cUmatic conditions, the difference between one 

 and two hoppers per beet making all the difference between success 

 and failure in crop production in certain cases. 



Believing that more definite information would be of value in dis- 

 cussing grasshopper control, the writer attempted to obtain estimates 

 of actual numbers concerned in some recent outbreaks. The results 

 proved to be of more value than anticipated, as by putting egg counts 

 and swarm counts together a better estimate of danger could be given 

 than formerly, and, also, that by using these actual figures the danger 

 was brought home to the people in a way to convince them and arouse 

 them to united action, such as had never before occurred. 



It is too bad that we cannot give the actual amount of food con- 

 sumed per hopper and translate a billion grasshoppers into bushels of 

 oats, bales of hay, or tons of sugar beets. 



In estimating the number of eggs laid by a swarm of Camnula pel- 

 lucida, the approximate area infested was determined after discing 

 the breeding ground so that the eggs showed on the surface (the breed- 

 ing grounds having been located the previous August). 



The heavily infested portion was found by counts to average: 



To the square inch 175 



To the square foot 25,000 



To the acre 1,000,000,000 



The area in one valley that was heavily infested was about twenty 

 acres or about twenty billion eggs ready to hatch. That statement was 

 sufficient to arouse the community, so that sixty teams and men turned 

 out for one day and destroyed them. 



The young hoppers start to migrate as soon as hatched and dry, 

 always traveling towards the sun. They travel only on warm days, 

 stopping if it clouds up and becomes cool or rains. In estimating the 

 numbers in one of the smaller migrating swarms, the central part of 

 about three hundred and twenty acres was found to average as follows : 



To the square inch 1 



To the square foot 150 



To the square rod 41,000 



To the acre 6,500,000 



To the square mile 4,000,000,000 



or that part of the swarm equalled two bilhon grasshoppers. Around 

 this center there was an average of from ten to fifteen to the square 

 foot on about four square miles, or one and one-third billion more, or 

 a total swarm of between three and four billion hoppers. This was 



