THE IMPORTATION INTO THE UNITED STATES OF THE 

 PARASITES OF THE GIPSY MOTH AND THE BROWN- 

 TAIL MOTH: 



A KEPOKT OF PBOG-KESS, 



With Some Consideration of Previous and Concurrent Efforts of this Kind. 



INTRODUCTION. 



By L. O. Howard, 



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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