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PREFACE. 



Bulletin No. 3 (new series) of this office, giving a full account of the 

 San Jose scale, was presented for publication, under the joint author- 

 ship of Doctor Howard and the writer, November 29, 1895, and 

 included the results of two years of very thoro study of the San Jose 

 scale. Two years later Doctor Howard issued, as Bulletin No. 12 (new 

 series), a record of the work to the end of 1897, more particularly giv- 

 ing an account of the spread of the San Jose scale in the United States 

 during the intervening period and the results of remedial work by this 

 office and the different experiment stations, together with additions to 

 the bibliography. It has now been more than ten years since the 

 publication of the larger bulletin giving the full life history of this 

 scale pest, and it seems advisable to issue a new general publication 

 to include in one bulletin the considerable additions which have been 

 made to our information on the subject. 



The portion of Bulletin 3 giving the life history of the insect was 

 worked out with great minuteness and is reproduced with little change. 

 The facts relating to the original home of the insect, as discovered by 

 the writer in 1901 in the course of explorations in China and Japan, 

 are incorporated in this bulletin, and the distribution of the insect has 

 been brought down to date. 



The literature of the last ten years relating to the San Jose scale is 

 of enormous volume, probably exceeding that relating to any other 

 insect pest. Most of this literature relates, however, to the strictly 

 economic phase of the subject — namely, distribution, injury to plants, 

 and the means of control — together with legal enactments of various 

 foreign countries and of the several States of the Union. The listing 

 of all the publications on the San Jose scale subsequent to its appear- 

 ance in the East in 1893 would make a bulletin of itself and would 

 probably serve no very useful purpose, and therefore no bibliography 

 is given in this publication. The earlier writings on this insect are, 

 however, recorded in Bulletins 3 and 12. 



The early experimental work with remedies given in Bulletin 3 is 

 omitted, and no effort has been made to summarize the enormous 

 body of reports on work with remedies recorded m the publications 

 of different experiment stations in this country. The results of the 

 later work with remedies conducted by this Bureau are to be found 



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