SCIENCE AND INDUSTRY. 
This remarkable insect also parasitizes the larve of solitary wasps, 
as well as the pup of a Tachinid fly, which itself parasitizes wasps. 
Tt is thus both a parasite and a hyperparasite. Graham-Smith (1916) 
reported that it was not only a parasite of fly pups, but acted as a hyper- 
parasite towards the above-mentioned Braconid Alysia. M. acasta 
is “capable of causing an immense amount of destruction. If it is 
usually a hyperparasite on the Braconid larve, it is not an insect to be 
encouraged, since it kills off large numbers of parasites very destructive 
to flies; if,°on the other hand, it usually attacks fly pupw during the 
summer months, it is most beneficial, its powers of destruction being so 
great; if, lastly, both Braconid and fly larve are commonly parasitized, 
its beneficial action is somewhat neutralized.” 
In view of thé above statement by such an authority as Graham-Smith, 
and in view of the fact that it is capable of parasitizing Tachinid flies 
and solitary wasps, which may be of considerable economic importance 
in controlling various insect pests, it would probably be unwise to 
introduce into Australia such a form as M. acasta as an agent for con- 
trolling the spread of flies. 
Dibrachys cavus, another chalcid, seems to be of value as a parasite 
of fly pups, but little information is available to us regarding it. 
The contents of this article may be summarized as follows:— _ 
1. There exist in Eastern Australia at least five hymenopterous para- 
sites which destroy flies (including sheep-maggot flies) namely, Spalangia 
muscidarum, Nasonia brevicornis, Chalcis calliphore, Dirrhinus sar- 
cophage, and Pachycrepoideus dubius. 
2. Of the various hymenopterous parasites known elsewhere as 
destroying fly pup, three others appear to be of outstanding import- 
ance, viz.:—Alysia manducator, Aphwreta cephalotes, and Melittobia 
acasta. The last-named acts also as a hyperparasite of many useful 
insects, and should not, in the light of our present knowledge, be intro- 
duced into Australia. The other two could apparently be safely intro- 
duced, if desired, to assist those parasites already present. The first- 
named seems to be especially valuable in this connexion. , 
