WiREWORMS. 75 



witli that degree of success for which we had hoped, and thus the 

 chief object of our investigations was not accomplished. But we 

 did succeed in proving the futility of many methods that have been 

 very generally recommended for the destruction of these pests ; 

 and it seemed wortli while to pubh'sh the detailed results of our ex- 

 periments, as given in Bulletin 33, for they might save farmers from 

 making expensive efforts that would surely bring no adequate returns. 

 Much has been written upon how to combat wireworms. And 

 yet, at the time Bulletin 33 was written (November, 1891), there 

 had not been published the results of a single extensive series of 

 carefully conducted experiments. Professor Forbes has recently 

 published some results he obtained in 1888 and 1891 (Seventh 

 Report, p. 48-49), and these wnll be noted in connection with the 

 discussion of our experiments. Most writers on this subject have 

 reasoned and written, but have not tested their theories. 



II. Methods of Experimentation. 



Under this heading in Bulletin 33, we described and figured the 

 different kinds of cages used in our experiments. As they are of 

 general interest to the working entomologist only, we will not 

 again discuss them. Suffice it to say in this connection that every 

 precaution was taken to keep the wireworms under as nearly 

 natural conditions as possible, and the experiments were conducted 

 in a systematic and careful manner. To eliminate possible sources 

 of error, comparative or check cages were used in each experiment ; 

 in these check experiments the cages were the same as the others, 

 only they remained untreated. So far as practicable, every method 

 was applied as it would be in the field. 



III. Experiments. 



Both defensive and offensive measures were used in our experi- 

 ments. Thus we tried to protect seed from the ravages of the 

 wireworms, and we also tried to destroy the insects in each of three 

 different stages of their existence — as wireworm or larva, pupa, 

 and adult; no eggs were obtained upon which to experiment. The 

 scope of our experiments was necessarily large as they embraced 

 nearly all the methods that we found recommended in the literature 

 of these insects. Only the general results can be given here ; they 



