io8 



Journal of Agricultural Research 



Vol. XII. No. 2 



from parasite attack and thus constantly liberates great numbers of 

 flies throughout the year and serves but in a small measure toward the 

 building up of favorable quantities of parasites. 



Table III. — Total parasitism by month of all larvcB of Ceratitis capitata collectedin 



Hawaii during igi6 



Month. 



Number of 

 larvse. 



Percentage of parasitism. 



Opius 

 humilis. 



Diachasvta 

 iryoni. 



Diackasvia 

 fuUawayi. 



Teirasti- 



chus gif- 



fardianus. 



Total. 



January.... 

 February.. 



March 



April 



May 



June 



July 



August. .. . 

 September 

 October. . . 

 November. 

 December. 



2,295 



1, 406 



7,161 



21, 619 



5,525 

 10, 013 



6,134 

 4,803 



5,631 

 7,972 

 6, 205 

 4,540 



0.4 



1-7 



2 

 6 



15 



13 



27 



34 



27 



25.2 



20. 9 



0.08 



. 2 

 .04 

 .09 

 . 009 

 .02 



•9 



•4 

 1.4 

 1.4 

 4.6 



6.98 



19- S 

 14.7 



37-64 



26. 69 



27. 809 

 18.52 



37-5 

 45-2 

 44-3 

 44-3 

 44.1 



A comparison of fruit-fly parasitism data secured during the years 

 1914, 1915, and 1 91 6 would indicate that the parasites now present in 

 the Territory have reached their maximum degree of development and 

 can hardly be expected to attain a greater control of the fruit fly than 

 that evidenced in 191 6. There has been some variation during the past 

 three years in the activities of the different species introduced, as already 

 noted in regard to the fluctuations in abundance of Diachasma iryoni and 

 Opius humilis; but the check upon the work of this pest by the present 

 parasites can hardly exceed its present limits. Some hope, however, is 

 yet felt for the parasite Tetrastichus gifjardianus Silvestri. It has grad- 

 ually increased in numbers about Honolulu since its establishment late 

 in 1 914. Certain valuable points in its favor may enable it, after further 

 acclimatization and general adaptation to new environment, to exceed 

 the work of the braconids and thus increase the total average parasitism. 



