100 l'HO("EEDlN(iS OF TIIK KOVAE S(!f'lETY OF (^UEENSLANn. 



A.— OBSERVATIONS ON THE BIOLOGY OF THE CHALCID 

 PARASITES OF AUSTRALIAN SHEEP BLOWFLIES. 



The chalcid wasjjs that parasitize sheep maggot-flies may 

 be divided into two groups according as they attack the pupa 

 or larva. Egg parasites have not yet been discovered. To 

 the former group l)elong Xasonia brevicornis, Paraspilomicrus^ 

 froggatti, Spalangia muscidarum, Dirhinus sarcophagce, Pachy 

 crepoideus dubius, and Hemilexomyia abrupta ; to the latter 

 group, Chalcis dipterophaga, Chalcis callipJwrce, and Australen- 

 cyrtus glraulti. 



1. Nasonia brevicornis Ashmead. (Figs. 5, 6, 7, 20, 21, 22, 



27-33.) 



A full description of this species -svas given by Girault and 

 Sanders (1909-191C). Its presence in Australia was detected by 

 Girault in October, 1911 ; two years later it was found by 

 Mr. Froggatt in N.S.W. and by Mr. E. Jarvis in Longreach, 

 Central Queensland. 



The wasp occurs very commonly in Brisbane, and can 

 generally be easily attracted by exposing deca3dng meat. 

 Careful observations on its life-history have been carried 

 out by W. W. Froggatt and T. McCarthy (1914, 1915), as well 

 as by J. L. Froggatt (1919). A more complete account which 

 includes the observations of these authors has been given by 

 Altson (1920). Graham-Smith (1919) also refers to this insect 

 in his work on the parasites of common house-flies. {See 

 also Johnston and Bancroft, 1920 ; Johnston, 1920.) 



In the following account, therefore, only a very brief 

 summary of published observations, supplemented by others 

 of our own, will be given. 



Length of Life-cycle. — Various observers have obtained 

 varying results ; Girault and Sanders give 15-22 J days, 

 according to the season, in America ; W. W. Froggatt and 

 McCarthy 11 to 15, and J. L. Froggatt gives 11-14 days, in 

 N.S.W. In Brisbane, during November, the. total period was 

 found by us to vary from 11 to 14 or even as much as 16 days, 

 while in January and February it occupied about 14 days. 

 Altson found that under lal;oratory conditions with a mean 

 temperature of 20° C. it averaged 21 days in London. 



Oviposition. — The ^^■asps are readily attracted to carrion. 



