ENEMIES. 127 



and valuable materials now in common use as 

 insecticides in the United States are 



(1) Arsenical Compounds ; 



(2) Emulsions of Petroleum ; 



(3) Pyrethrum. 

 



1. Arsenical Compounds. Paris green and London 



purple may be used in suspension in water in the 

 proportion of from half-a-pound to one pound of 

 the powder to forty gallons of water. When mixed 

 with flour or other diluent the proportion should 

 be one part of the poison to twenty-five or more 

 of the diluent. 



2. Petroleum Emulsions. A satisfactory emulsion 

 may be made in the following proportions : Kerosine, 

 i quart ; condensed milk, 12 fluid oz. ;4.diluted with 

 water, 36 oz. This is emulsified by violent churning, 

 and before use it may be diluted with water from 

 twelve to twenty times. Equal parts of kerosine 

 and condensed milk may also be thoroughly mixed 

 or churned together, and then diluted ad libitum 

 with water. 



3. Pyrethrum. Pyrethrum can be applied (i) as 

 dry powder ; (2) as a fume ; (3) as an alcoholic 

 extract, diluted ; (4) by simply stirring the powder 

 in water ; (5) as a tea or decoction. As a powder 

 it may be mixed with from ten to twenty times its 

 bulk of wood-ashes or flour, but before use should 



