SPRAYING ON THE BUNDS 35 



disposition to feed on them ; in fact, they appear to have 

 been left severely alone and no dead hoppers were to be 

 found on the treated bunds. 



2. Spraying on the bunds. 



For this experiment, a badly-infested grassy bund 

 about twenty feet wide was chosen and was divided up 

 into equal portions each about sixteen feet long. Each alter- 

 nate plot was left untreated while one plot was sprayed 

 with each of the six solutions mentioned above. The 

 spray did not spread well on the grass blades but it was 

 distributed as evenly as possible, about three gallons of 

 mixture being used for each plot. The spraying was done 

 from two to six o'clock in the afternoon and no rain fell 

 during that day or the following night. On the following 

 day, a light shower fell in the evening. A careful inspection 

 was made at the end of the second day but not a single 

 poisoned hopper was found. On the plots sprayed with 

 solutions A to D, the grasshoppers were present in normal 

 numbers and the solution had had no effect on the grass. 

 On the plots sprayed with solutions E and F, the grass was 

 badly scorched, most of it having turned brown. These two 

 plots were practically free from grasshoppers, but here, as 

 in the other, a very careful search revealed not a single dead 

 hopper. They had evidently deserted the plots for other 

 portions of the bunds where the grass was still to their 

 taste. 



The above two experiments show fairly conclusively 

 that poisoning baits or spraying with the above mixtures 

 is useless in combating this pest ; it seems very improbable 

 that any other combination of poison and sweetening 

 material would have yielded better results. 



3. Experiments tvith ]_Joisoiied bait in breeding cages. 



Finally, in order to ascertain if these poisons would 

 be effective in cases where the grasshoppers were com- 

 pelled to eat the poisoned bait or fast, 100 hoppers of the 

 fourth and fifth instars were placed in each of six large 

 field cages and were fed with grass upon which the various 

 solutions had been sprayed. The number of deaths at the 

 end of two days was as follows : — 



R. G. D 2 



