80 BULLETIN 536, U. S. DEPARTMENT OF AGRICULTURE. 



pest. Newman, in Western Australia, has found that a very large 

 percentage of the pupse are killed by a cold, wet winter when the 

 ground is frequently flooded. Such conditions so lessen, the abun- 

 dance of the fruit-fly that there are relatively few flies, numerically 

 speaking, to infest the early fruits of the succeeding season. On the 

 other hand, unusually severe outbreaks of the pest in both South Africa 

 and Australia have been attributed to exceptionally dry, mild winters 

 which made it possible for many adults to be present the following 

 spring to start large early summer generations. The successes attrib- 

 uted to clean cultural methods for the eradication of the fruit fly in the 

 apple orchards at Harvey, Western Australia, and possibly in New Zea- 

 land and Tasmania, may be due quite as much to the work of adverse 

 climatic conditions. The effect of climate upon fruit-fly development 

 can not be intelligently interpreted, inasmuch as previous writers 

 have not included climatological data with their statements. 



PARASITES. 



Ceratitis and Dacus Parasites. 



Literature contains numerous references to parasites reared from 

 various species of fruit flies. The only parasites discussed at length 

 here are those which have been successfully introduced and give 

 promise of being useful as factors in controlling Ceratitis capitata. 

 Of the parasites at present being reared from Ceratitis capitata under 

 natural conditions, Opius humilis is the only one reared originally 

 from this fruit fly. 1 All other parasites now known to attack Ceratitis 

 capitata in the field in Hawaii have adapted themselves to this host. 

 There appears to be no reason why certain others of the parasites 

 already reared from other fruit flies may not be used ultimately in con- 

 trolling the Mediterranean fruit fly. Silvestri records and discusses 

 the following parasites studied by him: 



BRACONID.E. 



Subfamily Opiinae: Opius concolor Szepligeti (ex Dacus oleae, Susa,Tunisia), O.rfaot-wto 

 Silvestri (ex Dacus oleae, Eritrea), 0. lounsburyi Silvestri (ex Dacus oleae, Transvaal), 

 0. dexter Silvestri (ex Dacus longistylus, Dakar, Senegal), 0. perproximus Silvestri (ex 

 Dacus brevistylus and Ceratitis giffardi, Kotonou and Segboroue, Dahomey), 0. per- 

 proximus modestior Silvestri (ex Ceratitis nigerrima Aburi, Gold Coast, and Olokemeji, 

 Nigeria), 0. humilis Silvestri (ex Ceratitis capitata, Constantia, Cape Colony), 0. in- 

 consuetus Silvestri (ex Ceratitis tritea, Olokemeji, Nigeria), 0. inquirendum Silvestri 

 (identity of host unknown, Victoria, Kameruri), 0. africanus Szepligeti (ex Dacus oleae, 

 South Africa and Transvaal), 0. africanus orientalis Silvestri (ex Dacus oleae, Eritrea), 

 Hedylus giffardii Silvestri (ex Ceratitis punctata, Conakry, French Guinea), Diachasma 

 fullawayi Silvestri (ex Ceratitis giffardi and tritea, Dakar, Senegal, Olokemeji, Nigeria, 

 and Kakoulima, French Guinea), D . fullawayi robustum Silvestri (ex Dacus bipartitus, 



1 The writers reared a single specimen of a parasite from a C. capitata pupa which was identified by D. T. 

 Fullaway as Spalangia sp. It seems probable that this was primarily a parasite of some other dipteron, as 

 no other specimens were reared. 



