4 PREFACE. 



in the five different editions of Circular 42, relating to the control of 

 the San Jose scale, and in the two editions of Circular 52, relating to 

 the lime, sulfur, and salt wash, and also in several articles in the 

 miscellaneous bulletins of the Bureau. 



Inasmuch as a good deal of the present bulletin has been rewritten, 

 and as most of the added matter is from articles published by the 

 writer, at the suggestion of Doctor Howard this publication is issued 

 as a new bulletin of the Bureau series and under single authorship. 

 Considerable matter, however, from Bulletin 3, notabl}^ that relating 

 to life histor}^ and habits, has been used, as already indicated, with 

 little change; this publication is largeh^, therefore, a compilation, with 

 the aim of bringing the subject down to date and making it complete 

 and available as a means of present information on the habits and 

 status of this important scale insect pest. 



The portion on true parasites (pp. 58-62) was kindly prepared by 



Doctor Howard, who has long been the authoritj^ on this group of 



parasitic four- winged flies. , 



C. L. M. 



I 



