G. S. Graham-Smith 
537 
insect are plainly visible. The pupa later becomes brown and then 
black. The pupal stage occupies about five days. 
“ The adults usually gnaw one hole in the puparium and escape, 
although two may sometimes be made. 
“ The time occupied from oviposition to the emergence of the adult 
is fifteen days, but there are indications that this varies with the 
temperature. The males characteristically appear a little before the 
females, and are active little creatures, continually running over and 
over the empty pupal cases. As soon as the females emerge copulation 
begins, the females being at once ready to receive the males. 
“ From each parasitised pupa both sexes may emerge, but females for 
the most part predominate. 
“ The number of parasites in each pupa varies considerably, and has 
been found to be as low as two, while in one instance there were as 
many as seventy-five, which latter batch were much smaller than the 
typical specimens, due no doubt to the supply of food being inadequate. 
In most cases, however, the number developing in a single pupa has 
been found to be between twenty-five and thirty-six parasites. The 
number of eggs laid by a single female parasite at one puncture has 
not been determined....The number of eggs laid by a female also 
seems to vary. In three instances one female placed in a tube with 
fifteen pupae parasitised the whole, with the exception of two pupae 
which had decayed. The total number developing from the one 
parasite in the first case was 140, in the second 148, and in the third 96.” 
(The numbers emerging from each pupa varied from 15 to 1 in these 
experiments.) 
“ The parasites, on the whole, are very hardy little creatures, and 
under careful treatment should five several weeks.” 
McCarthy produced ten generations in six months and supplied 
thousands of parasitised pupae to various parts of the State of N.S.W. 
with the intention of attempting to keep down the blow-flies, which 
do great damage to the sheep. 
Conclusions. 
1. Amongst the common species of flies the very great majority 
of individuals pass the winter as pupae, or more rarely as larvae, which 
pupate early in the spring. The pupae or larvae are situated under 
shelter on the surface or more commonly are buried within two or 
three inches of the surface of the ground. 
2. A very small and unimportant minority of both sexes emerging 
