KNOWN AND RECORDED PARASITES. 93 



Native (American) Tachinids Reared from Euproctis chrysorrhcea L., at the 

 Gipsy Moth Parasite Laboratory. 



Phorocera saundersii Will. ? Phorocera leucanix Coq. 



Euphorocera claripennis Macq. Tachina mella Walk. 



Exorista hoarmix Coq. 



N. B. — The above species have only been reared very occasionally. The species, however, doubtfully 

 referred to Phorocera leucanix Coq. has been reared through to the pupal stage in considerable numbers. 

 These pupae have always been imperfect and "larviform" and at the time of writing none has been reared 

 through to the adult. 



The compilation of the catalogue of parasites was originally under- 

 taken in the expectation that it would prove of great service upon 

 exactly such occasions as the present, when the application of the 

 theory of control by parasites should be put to the test. Its value 

 naturally depended upon the accuracy of the original records, and it 

 was only right to suppose that in the majority of instances these 

 could be depended upon. It was equally natural to suppose that 

 the parasitic fauna of such common, conspicuous, and widely dis- 

 tributed insects as the gipsy moth and the brown-tail moth would 

 be well represented in these lists, which were based upon a thorough 

 overhauling of European literature, and it was not expected that any 

 parasites of particular importance would be found which were not 

 thus recorded, unless, indeed, they were confined to Continental Asia 

 or to Japan. 



In the fall of 1907, as soon as the turmoil of his first summer's 

 work permitted, the junior author attempted to make use of the 

 numerous bibliographical references for the purpose of learning as 

 much as possible of the insects with which he was to deal. One 

 after another, various species were taken up, until he was in possession 

 of practically all of the published information concerning perhaps 

 half of the Hymenoptera listed. Then he stopped, because the 

 information thus gained was obviously not worth the labor. It was 

 not so much that recorded information was scanty, or lacking in 

 interest, but it was because in a great many instances it was contra- 

 dictory to the results of the actual rearing work which had been 

 carried on in the laboratory throughout the summer. It was obviously 

 impossible to accept everything at its face value, and apparently 

 next to impossible to choose between the true and the false. But 

 one thing remained to be done, and that was to determine at first 

 hand everything which it was necessary to know concerning the 

 numerous species of parasites which it was desired to introduce into 

 America. 



If the list of parasites which have been reared at the laboratory 

 from imported eggs, caterpillars, and pupae of the gipsy moth and 

 the brown-tail moth be compared with the lists which have already 

 been given, the numerous and obvious differences which are immedi- 

 ately apparent will serve better than words to illustrate the situation 

 which confronted us at the close of the season of 1907. 



