26 RESULTS FROM GIPSY MOTH PARASITE ' LABORATORY. 



ally be found some which created rather than took advantage of the 

 conditions under which they were encountered. It required hardly 

 any stretching of the imagination to conceive of sarcophagid maggots 

 deposited upon living pupae, effecting an entrance, and eventually 

 bringing about the death and decomposition of the host. From time 

 to time tentative attempts to acquire more definite information were 

 made, but without positive results one way or the other. Large num- 

 bers of gipsy-moth pupse, apparently living, were collected in the 

 open and upon one or two occasions sarcophagid maggots were sub- 

 sequently found, but there were always very satisfactory explanations 

 for their presence other than that they were parasitic, and it was 

 increasingly evident that if such experiments were to be decisive, they 

 would have to be conducted with exceedingly great care. Several 

 attempts were also made to keep the adult sarcophagids reared from 

 gipsy-moth pupae imported from Europe or Japan until they 

 reached their full sexual development and were ready to deposit 

 iheir brood, but there were a good many things to learn about the 

 best way of conducting an experiment of this sort and none of them 

 was successfully concluded. 



In the summer of 1910 the question of Sarcophaga in its relations 

 to the gipsy moth was rather suddenly reopened as the immediate re- 

 sult of a study in parasitism conducted by Mr. P. II. Timberlake, of 

 this laboratory, upon the " pine tussock moth " which was causing 

 some injury to pine in northern Wisconsin. The results of his studies, 

 which will be published in another part of this bulletin, were such 

 as strongly to indicate the parasitic character of certain sarcophagids 

 and to suggest that they were, in effect, of rather considerable im- 

 portance in the control of this moth. 



This, when taken in connection with the fact that a vastly larger 

 number of sarcophagids were continually being received in ship- 

 ments of gipsy-moth pupae from Europe and Japan than would be 

 secured from an equal number of similar pupae collected in America, 

 was a circumstance which could no longer be overlooked. The evi- 

 dence was such as materially to support a contention that among the 

 European sarcophagids occurred species which were primarily ene- 

 mies of the gipsy moth. If, as did not seem so very improbable, there 

 existed in Europe such an important group of dipterous parasites of 

 gipsy-moth pupae, no time should be lost in attempting to secure their 

 introduction into America. 



Most unfortunately it is impossible in this case, as in a great many 

 others, to conduct the necessary investigations to the best advantage. 

 Independent European entomologists can not, of course, conduct 

 elaborate investigations along lines wholly outside of their own 

 affairs, and the establishment of a European branch of the Gipsy 

 Moth Parasite Laboratory has never been considered as practicable. 



