Experimental work with grasshopper baits was carried on over a period of three years with a two-fold purpose in view, first, to determine the merits, under Colorado conditions, of the ingredients commonly used in standard grasshopper baits; and second, to find a more practical killing agent than white arsenic. Amyl acetate and salt arc essential elements of an efficient grasshopper bait. A combination of bran, arsenic and water only, gave surprisingly good results, but not. good enough for practical usage. The value of expensive molasses is doubtful. Only when cheap sugar beet refuse molasses can be obtained does it seem justifiable to include it. The substitution of 50% by bulk of sawdust in place of bran in baits to. be used on lands of low productive value per acre, is recommended. .Fermentation of the bait to replace the use of amyl acetate gave poor results when used for our economic species of A crididae but excellent results in the case of A navrus simplex. The superiority of sodium arsenite over white arsenic was established by two years of experimentation and its extensive use in two large epidemics of grasshoppers. As a killing agent, it is fully as efficient as the best mixed white arsenic and is more practical in mixing, cost and handling.