153 



Parasitism Among the Larvae of the Mediter- 

 ranean Fruit Fly (C. Capitatd) in Hawaii 



During 1914 



BY 



E. A. Back and C. E. Pemberton, 



Bureau of Entomology, 



United States Department of Agriculture. 



W. M. Giifard, Esq., 



President and Executive Officer, 



Board of Agriculture and Eorestry, 

 Honolulu, T. H. 



Sir: 



It will be recalled tliat at tlie time the Federal Bureau of 

 Entomology began its investigation of the Mediterranean Fruit 

 Ely (Ceratitis capitata) in the Hawaiian Islands in August, 1912, 

 you made the request of Mr. C. L. Marlatt, Assistant Chief of 

 the Bureau of Entomology, and entomologist directly in charge 

 of this investigation, that the Bureau leave to your Board the 

 problem of finding, introducing and establishing parasites of this 

 pest in Hawaii, inasmuch as your Board had already engaged the 

 services of Dr. F. Silvestri for this purpose. The writers have, 

 therefore, confined their efforts to other phases of investigational 

 work, and such information as they have secured has been 

 obtained quite incidentally to their other work. They have, how- 

 ever, been forced recently to take an added interest in the para- 

 sites introduced and established by the very frequent occurrence 

 of parasites among the fruit flies used in their experimental work, 

 and in the marked decrease of the pest in certain districts with 

 the resulting effect upon the degree of infestation of host flies. 



This active interest began during July, 1914, when the 

 writers were confronted in their biological work with a parasitism 

 ranging from 29 per cent to 53.8 per cent among certain pupae de- 

 rived from strawberry guavas (Psidium cattJeyanum). Since 

 that time it has been the custom of the writers to take from lots 



