490 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1926 
(c) Where the original home is known, but its parasites and their 
interrelations are not known. 
(d) When there is a close morphological relative to the injurious 
form in some other country, whose parasites may be expected to 
take readily to the species aimed at or whose mode of life is so similar 
as to excite an oviposition impulse from its parasites. 
In 1911, in recounting the original plan for the introduction of 
the parasites of the gypsy moth and the brown-tail moth, I wrote 
(Bulletin 91, Bureau of Entomology, pp. 13, 14)— 
It seemed to the writer that by attempting to reproduce in New England 
as nearly as possible the entire natural environment of the gypsy moth and 
the brown-tail moth in their native homes, similar conditions of comparative 
scarcity could surely be reached, and this view he still holds with enthusiasm. 
In this statement, I think to-day that I well expressed the funda- 
mental idea, and that the study of “ the entire natural environment ” 
is essential in most of these problems. This is only another way of 
expressing the need for extended ecological work. 
A final word in regard to the too optimistic predictions of en- 
thusiasts: We have seen in California the unfortunate results of too 
much optimism. We have seen also, within the past few years, the 
sudden discovery of the descendants of importations of parasites 
which had been here unnoticed but gradually increasing for from 
20 to 25 years; which means that, not only must we not be over- 
confident, but also that we must not be too easily discouraged. I like 
to remember, in regard to the first point, the concluding words of 
Froggatt after his tour around the world in 1907 and 1908, in his 
report on his expedition— 
Let the whole question be judged on its results. Allow that one or two 
experiments have shown perfect results * * * that can be no reason 
why the parasite cure alone should be forced upon any one. Its admirers 
should be perfectly honest. * * * The wisest can never be sure of the 
results of any experiment. * * * Those at work for its (economic ento- 
mology’s) far-reaching interests could do it no greater harm than by 
misleading or unproved statements. 
As to the place of parasitism in plans for insect control: 
It should receive consideration in all cases of imported pests just 
as soon as it is decided that extermination is likely to be impossible. 
Studies of the parasites in the native home of the pest should be 
begun at once, and, in the case of serious loss, no expenditure con- 
sistent with rigidly scientific methods should be begrudged. Work 
of this kind is in its infancy, and its possibilities are great. 
Sa > 
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