were placed on each. These experiments were carried on in dupli- 

 cate, and cages wilh larvae on unsprayed food were placed by the 

 side of them as a check. 



The proportion of f pound and less to 150 gallons of water did not 

 prove satisfactory, for although many of the larvae were soon killed 

 some remained alive after eight days. 



The proportions above f pound to 150 gallons of water proved 

 entirely satisfactory, as they killed all of the larvae within three days, 

 and in no case did the arsenate of lead injure the foliage. 



HOW TO PREPARE ARSENATE OF LEAD. 



A convenient way to prepare this insecticide is to put 11 ounces of 

 acetate of lead and four ounces of arsenate of soda into a hogshead 

 containing 150 gallons of water. These substances quickly dissolve 

 and form arsenate of lead, a fine, white powder which remains in 

 suspension in water. 



It is highly desirable to add two quarts of glucose, or if that can- 

 not be obtained, two quarts of molasses to each 150 gallons of water 

 used, for the purpose of causing the insecticide to adhere to the 

 leaves. 



The experiments with this insecticide both here and in Maiden last 

 summer indicate that it will remain on the trees for a long time, even 

 after quite heavy rains. 



WHERE TO OBTAIN THIS INSECTICIDE. 



The acetate of lead and arsenate of soda from which the arsenate 

 of lead was made for the experiments at Maiden and also at this 

 place, were obtained of Billings, Clapp & Co. of Boston, Mass. They 

 furnish a good quality of arsenate of soda at eight cents a pound and 

 acetate of lead at fourteen cents a pound in twenty-five pound quan- 

 tities. It is possible that cheaper grades would give equally good 

 results. It should be borne in mind that acetate of lead, arsenate of 

 soda, and arsenate of lead are all poisonous and should be used with 

 as great care as Paris green. 



ADVANTAGES OF THIS INSECTICIDE. 



It is too early to say that this is a better insecticide than Paris 

 green, under all circumstances and for all insects, but it has the 



