1909.] PUBLIC DOCUMENT- -No. 73. 69 



In conclusion, I recommend the following :- 



1. The artificial suppressive measures to be carried on with vigor 

 wherever it is possible and convenient, except in the locality in the 

 central part of the infested territory set apart for the multiplication of 

 the parasites. 



2. Vigorous suppressive measures along the streets and on the borders 

 of the infested territory, in order to prevent as much as possible the 

 extension of the area of infestation. 



3. The study of the biology of the parasites in Europe and in Japan, 

 in order to profit by such study in the introduction and rearing of 

 parasites. 



4. The continuation of the collection of parasites in Europe and in 

 Japan, liberating the same in America in localities set apart for each 

 species of parasites that are recognized surely to be of the first rank. 



What will be the final result of this fight? I believe that the results 

 will be the best, because as far as I can see it seems that there can 

 be no obstacle in the way of acclimatizing in America some at least 

 of the parasites of Lymantria and Euproctis, and that surely at the 

 end of some years there will be a large number of parasites working 

 against these insects. For some years, then, it will be well to continue 

 the suppressive artificial methods, only being careful not to destroy the 

 parasites (a thing that will be in part at least possible) ; and after 

 the work is left to the parasites, the specimens of the gypsy and brown- 

 tail moth will be reduced to a negligible number. It is well known that 

 they still have in Europe serious infestations of these insects at in- 

 tervals. This is because the parasites have in their turn other enemies, 

 primarily among these other parasites. Here in America, if care is 

 taken not to liberate the secondary parasites with the primary parasites, 

 the gypsy moth and brown-tail moth will always have many enemies. 



Also, if the final result of the introduction of the parasites should 

 not be as happy as it is foreseen, nevertheless, it would be sufficient 

 to accomplish by their means the result of combating efficiently enough 

 the gypsy and brown-tail moths. 



Therefore, I for my part felicitate you and Professor Howard for 

 what you have done both in science and in practice, and so much the 

 more that in the present case the national economy, whose prosperity 

 stands highly to every citizen of the United States, is seriously 

 concerned. 



Perseverance, then, and confidence in this warfare, since I believe 

 your success will be complete, at least if nature does not conceal some 

 new and unexpected weapon of defense. 



I thank you for the kind invitation to expound fully my opinion 

 about the work under your direction, and with best wishes for your 

 distinguished health, I am, 



Yours most sincerely, FILIPPO SILVESTRI. 



