THE IMPORTATION INTO THE UNITED STATES OF THE 
PARASITES OF THE GIPSY MOTH AND THE BROWN- 
TAIL MOTH: 
meio Ont OF PROGRESS, 
Wirn Some CoNSIDERATION OF PREVIOUS AND CONCURRENT EFFORTS OF THIS KIND. 
INTRODUCTION. 
By L. O. Howarp, 
Chief, Bureau of Entomology. 
As will appear from the opening portion of this bulletin, which 
gives an account of previous work in the practical handling of natural 
enemies, carried on in various parts of the world, nothing comparable 
to the work which is to be described has ever before been undertaken. 
As will appear also, most of the successful work in this direction has 
been done with the fixed scale insects. The exceptions to this gen- 
eral statement among the measurably successful efforts have been the 
introduction of parasites of the sugar-cane leafhopper into Hawaii, 
some reported work in the introduction of South American natural 
enemies of fruit flies into Western Australia, and the introduction of 
one of the many European enemies of the codling moth from Spain 
into California; but it does not appear that practical results of any 
very great value have been achieved by the last two introductions, 
although information from Western Australia is scanty. At the 
time when the work began nothing practical had been accomplished 
with the natural enemies of any lepidopterous insects, and in the whole 
history of the practical handling of parasites no work of this character 
has ever been attempted upon anything like the large scale with 
which the present work has been carried on. Some studies had already 
been made both by the writer and by Mr. Fiske on the subject of the 
intensive parasitism of two native species of American moths, and 
for years the bureau had been keeping records of the rearings of 
parasites of lepidopterous insects as well as of others; moreover, the 
writer had made a careful study of the records of the rearings of 
hymenopterous parasites from host insects all over the world and 
had accumulated an enormous catalogue of such records. Never- 
theless the initial work on such a scale was experimental in its charac- 
ter. It seemed to the writer that by attempting to reproduce in New 
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