284 JOURNAL OF ECONOMIC ENTOMOLOGY [Vol. 14 



mash containing Paris green lived for an average of 35.5 hours after 

 being poisoned, the 19 individuals receiving the white arsenic mash 

 lived for an average of 43.9 hours after poisoning, and those poisoned 

 by crude arsenic mash continued to live for an average of 50 hours 

 after poisoning. The poison mash mixed with Paris green killed quick- 

 er than the others, that mixed with crude arsenic being an average of 

 14.5 hours slower. The average length of time taken for the white 

 arsenic to kill was about midway between the Paris green and crude 

 arsenic. 



The amount of poison bran mash required to kill grasshoppers and 

 the effect of different amounts consumed on the rapidity of kill and 

 amoimt of food eaten after poisoning was next considered. These ex- 

 periments were performed by allowing the hoppers to feed on poisoned 

 mash (K lb. Paris green and 2 quarts black strap molasses for each 25 

 lbs. of wheat bran) for different lengths of time, thus constiming differ- 

 ent amounts. These were then placed in individual cages and treated 

 similar to the hoppers in the experiments previously shown. 



The following table shows the length of time between poisoning and 

 death and the amount of food eaten after poisoning by hoppers receiv- 

 ing different amounts of poison bran mash. 



Table IV 



No. hoppers Time allowed to Average time Average amount of 



used feed on poison between poisoning corn leaf eaten between 



bran mash and death poisoning and death 



These data apparently show that the hoppers receiving the smallest 

 amount of poison bran mash died quicker and ate less after being poi- 

 soned than any of the other groups. However, one of the hoppers in 

 this group failed to become poisoned at all, and must be taken into con- 

 sideration. Those hoppers which fed on the poison for 3 minutes 

 lived longer and ate more than any of the other groups. 



Summarizing the data set forth in this paper, it can be said that al- 

 though grasshoppers may appear healthly and active for many hours 

 after eating poison bran mash, they consume very little food as com- 

 pared with unpoisoned hoppers, the data showing less than one ninth 

 as much. Because of this no farmer who has poisoned should be dis- 

 couraged if the hoppers remain active in fields for a considerable period 



iQne hopper from the 30 seconds group failed to become poisoned. 



