s^ 



( HALCID PARASITES. 



p. 360-371, fig.-?. 10-12). There is a very marked sexual" 

 dimorphism, the male possessing rudimentary ^\-ings and 

 eyes, as well as ])eculiarly modified antenna-. The female 

 can live in confinement for a long period (33 to 30 days 

 average — l»o the maximum noted) and lay up to 300 eggs. 

 The males have a short life and do not leave the puparium 

 in which they were de\'eloped. 



This remarkable insect alr-o parasitit-es the larva:- of 

 solitary wasps, as well as the pupae of the Tachinid fh' which 

 rtself parasitises the wasps (MalJ'she^" 1913, fide Graham- 

 Smith 1919, p. 371). It is thus both a parasite and a 

 hyperparasite. HoAvard and Fiske (1912) whose remarks 

 are quoted by Graham-Smith (1919, p. 368, 370), found it 

 attacking several kinds of fly ])uparia (including Tachinids) 

 and hymenopterous cocoons. Graham-Smith (1910, p. .333) 

 reported that it was not only a parasite of fly pupse, but 

 acted as a hyperparasite towards the above mentioned 

 Braconid Alysia. J/, acasta is ' capable of causing an 

 immense amount of destruction. If it is usually a hyper- 

 parasite on the braconid larvfe it is not an insect to be 

 encoiuaged, since it kills off large numbers of parasites 

 very destructive to flies ; if, on the other hand, it usually 

 attacks fly pupte during the summer months it is most 

 beneficial, its powers of destruction being so great : if, 

 lastly, both braconid and fly larvae are commonly parasitised, 

 its beneficial action is somewhat neutralised." 



In view of the above statement l)y such an authority 

 as Graham- Smith, and in view of the fact that it is capable 

 of parasitising Tachinid flies and solitary Avasps A\hich may 

 be of considerable economic importance in controlling 

 various insect pests, it would probably be unwise to intro- 

 duce into Australia such a form as J/, acasta as an agent for 

 controlling the spread of flies. 



Dihrachys earns, another chalcid, seems to be of value 

 as a parasite of fly pupie, but little information is available 

 to us regarding it (Graham-Smith 1919, ji. 371-2, Fig. 13). 



None of the foregoing insects were bi'ed out by Mellor 

 (1919) during his work on the habits of various English 

 flies. 



