REPORT OF THE ENTOMOLOGIST. 213 



Manufacturing company, of Seneca Falls, N. Y. Of course any other 

 good pump will answer the purpose. Fig. 25 shows the use of this 

 pump from a wagon. It will work equally well with double or sin- 

 gle discharge pipe, or for the application of arsenical or kerosene 

 preparations. 



THE ARSENITES. 



Under the name of arsenites we have two very effective insecti- 

 cides. These are the London purple aud Paris green of commerce. 

 The first is an arsenite of copper, and the second an arsenite of lime. 

 They are both preferable to the white arsenic itself for use as insecti- 

 cides on account of their color, which acts as a sort of safeguard against 

 accidents, and also from the fact that they are more readily held in 

 suspension. The London purple, made by Hemingway's London 

 Purple Co., of London, England, is much cheaper than the Paris 

 green, and is just as effective in its work on the many insects for which 

 the latter has been recommended and used. Professor A. J. Cook, in 

 a recent bulletin, writes as follows about these two insecticides :* 



"As London purple is much cheaper than Paris green, costing only 

 fifteen cents per pound, and is just as effective in practical use, it 

 should always be used when it can be had, unless on very tender foli- 

 age, like that of the peach, when only Paris green should be made use 

 of. It is still a question if the arsenites should be used on the peach. 



" London purple may be used either dry, mixed with land plaster 

 — one pound of the poison to eighty or one^hundred pounds of the 

 plaster — or mixed with water — one pound to two hundred gallons 

 of water. 



" It is not the strength of the mixture, but the force and thorough- 

 ness with which it is applied, that secures success. The water mix- 

 ture, which will usually be most satisfactory, should be kept well 

 stirred, that the heavy mineral poison may not settle." He goes on 

 and states further that London purple "Should never, be applied 

 to fruit trees till the blossoms fall from the trees;" and that 

 it "should be applied to apple trees but once, except in case of very 

 heavy rains, when it should be repeated two or three weeks after the 

 first application ; should be used two or three times at intervals of ten 

 days or two weeks on the plums, and after every heavy rain ; may be 



* Bulletin No. 58 of the Michigan Agricultural College Experiment Station. 



