84 PARASITES OF GIPSY AND BROWN-TAIL MOTHS. 
ingly the junior author was commissioned to visit France, Italy, and 
Russia in the winter and early spring of 1911, and subsequently to 
spend the breeding season- if found desirable, in Japan. He was 
given authority to employ the necessary agents in each of these coun- 
tries. He sailed January 5, 1911. 
KNOWN AND RECORDED PARASITES OF THE GIPSY MOTH AND OF 
THE BROWN-TAIL MOTH. 
When the work of introducing the parasites of the gipsy moth and 
of the brown-tail moth was begun in 1905, the available assets con- 
sisted of generous appropriations by the State of Massachusetts -and 
the Federal Government, an abundant faith in the validity of the 
theory which was to be put to test, and a long bibliographical list 
of the parasites which were recorded as attacking these insects in 
Europe and Japan. Of these, the appropriations have withstood 
most effectively the ordeal of the years which have since passed. 
Our faith in the validity of the principle at stake has also stood out 
wonderfully well, when the numerous trials to which it has been 
subjected are taken into consideration. It is not too much to say 
that at the present time it is stronger than ever, notwithstanding 
that a good many facts have come to light in this period which -are 
more or less flatly in contradiction to the theory of parasite control 
as generally accepted at the beginning. It has more than once been 
necessary to modify beliefs and ideas as previously held, in order to 
make them conform to the actual facts. To take a pertinent exam- 
ple, it was necessary to place an entirely different value upon the 
bibliographical list above mentioned than that which was placed upon 
it when the work was begun, and when the policies of the laboratory 
were first determined. 
Nearly thirty years ago the present head of the Bureau, of Ento- 
mology undertook the compilation of a card catalogue of references 
to the host relations of the parasitic Hymenoptera of the world. 
For more than twenty years the work was continued until some 
30,000 such references were accumulated. From among them those 
in which the gipsy moth was mentioned as the host were collected 
and a list of gipsy-moth parasites was published in Insect Life. 1 
With the exception of a comparatively few recent additions this list 
forms the basis of that which follows. That of the parasites which 
have been recorded as attacking the brown-tail moth is largely from 
the same source. 
1 U. S. Department of Agriculture, Division of Entomology, Insect Life, vol. 2, pp. 210-211, 1890. 
