286 JOURNAL OF ECONOMIC ENTOMOLOGY [Vol. 14 



servation it was necessary to approach so close to the bait that part of 

 the hoppers were frightened away. Several types of traps were con- 

 structed, any of which would successfully retain the hoppers, once they 

 had entered, thus making possible an accurate count. All of these were 

 unsuccessful since the hoppers apparently preferred to observe the bait 

 from the outside rather than enter the trap and feed. 



Next, a few experiments were tried with a pair of army field glasses 

 (Prism stereo 6 power) with which it was possible to make accurate 

 counts with the observer stationed from twenty to thirty feet from 

 the bait.. The grasshoppers seemed to have no objection to this meth- 

 od of procedure and it proved so satisfactory that all the data record- 

 ed in this paper were secured by the aid of these glasses. 



All bait combinations were mixed in pmall batches, care being taken 

 to add the various ingredients in their exact proportions. Equal a- 

 mounts of the various baits were placed, each in the center of a heavy 

 card-board disc, one foot in diameter and checked off in squares by 

 heavy black lines to make the ^otmts both easier and more accurate. 



All hoppers observed feeding or within the six in.:h radius of the bait 

 were included in each count, these counts being made at short inter- 

 vals throughout the day. In order to eliminate any possible error due 

 to greater abundance of grasshoppers in some locations, in all experi- 

 ments the position of the cards was interchanged after every few counts. 

 Thus the number of hoppers attracted to the various combinations of 

 materials used in the baits was accurately determined. Most of the 

 experiments were performed on a tract of uncultivated land covered 

 with a rank growth of weeds and heavily infested with grasshoppers, 

 M. jemur-ruhrnm being by far the predominating species. 



In the following experiments 16 flavors were used in 26 different 

 combinations. The tables show the flavors which were run side by side 

 on the same day, the number of counts made on each, and the total 

 number of hoppers counted at each bait during the day. In these 

 tables the word molasses is given for the common black strap molas- 

 ses. The proportions in which the various flavors were used are as 

 follows:- Black strap molasscF, 2 quarts to 25 lbs. of bran. Fusel oil, 

 anise oil and lemon extract, from 1 to 2 oimces to 25 lbs. of bran. Cider, 

 vinegar, and grape juice, 1 quart to 25 lbs. of bran. Watermelon,can- 

 telope, tomatoes and apple pomace, enough to make 1 quart to each 

 25 lbs. of bran. 



