United States Department of Agriculture, 



Division of Entomology, 

 Washington, D. C, March 1, 1891. 

 The following information relative to kerosene emulsion, resin 

 wash, and arsenical mixtures has been placed in circular form to 

 enable ready and full reply to letters which are constantly being 

 received in reference thereto. It is not intended to be a complete 

 consideration of the question of insecticides, but is drawn up to 

 meet those questions which experience has shown are most often 

 asked by correspondents. 

 Respectfullv, 



C. V. Riley, 



Entomologist. 

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