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, notably that relating 
to life history and habits, has been used, as already indicated, with 
little change; this publication is largely, 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 authorit} r on this group of 
parasitic four- winged Hies. 
C. L, M. 
