February, "21] parker and seamons: grasshopper baits 139 



Since the experiments were conducted primarily to determine the 

 relative value of the various flavoring materials, they were used at the 

 strength recommended for immature grasshoppers, i. e., twice as strong 

 as when used against adults. This was done so that each kind of bait 

 would have a strong distinctive odor of its own. 



Method of Putting Out Baits 



In the first experiments the various baits were scattered on boards 

 and over small plats in areas 30 yards apart where grasshoppers appeared 

 to be uniformh- distributed. The number of grasshoppers feeding at 

 each board was recorded every twenty minutes and counts of dead 

 grasshoppers were made on the plots at the end of two daA'S. This 

 method did not prove satisfactory as it was observed that the grasshop- 

 pers mo\'ed about during the day and that their distribution was by 

 no means uniform or constant. In other words, the scarcity or abund- 

 ance of grasshoppers in the vicinity of any particular bait had a much 

 greater bearing on the results than did the relative attractiveness of the 

 bait itself. 



Where observations are made every twenty minutes there is too 

 great an element of chance for satisfactory results. At the particular 

 mom.ent the observation is taken the grasshoppers may have momen- 

 tarily ceased feeding because of a passing cloud or gust of wind, while a 

 few minutes before they may have been feeding very heavily. The 

 results of the first experiments were so variable that they were not 

 reported. However, it should be stated that in practically every test 

 amyl acetate was far ahead of all the others that were tried. 



In order to overcome the question of uneven distribution and the 

 element of chance in making observ^ations, it was decided to conduct 

 all tests at one point and have them under continuous obser^^ation. 

 Each kind of poison bran mash was placed in a small tin pan six inches 

 in diameter and one inch deep. The pans were arranged in a three foot 

 circle where adults of Camnula pellucida Scudd. had gathered in large 

 numbers for breeding, and egg laying. An observer stationed ten feet 

 from the pans watched with field glass and recorded every grasshopper 

 that climbed into a pan and actually fed. The relative position of the 

 pans in the circle was changed and fresh bait was put out every two 

 hours. All of the experiments reported on were conducted in this way. 



Results of E.xpepiments 



Experiments were conducted on August 1, G, and 7, during which 

 time 2074 grasshoppers climbed into the pans and registered their 

 choice. 



