14 
American forms and appear to have come in from the 
south, others have come in at different periods and prob- 
ably by different routes from the north and freouently 
have near relatives in New Guinea or the East Indies. 
One of our members, I. M. Mackerras, has written on the 
origins of the different groups of Diptera. 
We used to think of our mosquitoes as rather nicely 
divided into northern forms, which did not get much south 
of the Queensland border, and southern forms which rarely 
got north of it, though of course there were always some 
known to liave a wide distribution. Rut now, due to the 
intensive collecting done by myxomatosis workers in the 
south and the Mosquito Control Committee's collections 
from Queensland, these ideas need adjusting. To quote 
one example, a species of the tropical Aedes kocJii group has 
recently been found in southern Victoria. 
The answer to distribution within the continent lies, 
T think, in the sort of Avork Mattingly is doing on African 
mosquitoes. Climate and vegetation, both past and present, 
have influenced the distribution of species. J. Gentilli has 
discussed this very fully in relation to the distribution of 
Australian birds, Avhich of course are much better known 
than other groups of animals. For si^ch a discussion one 
needs accui'ate identifications, many locality records and 
also a knowledge of the ecology or natural hi'-’tory of a 
species, that is, the kind of environment in which it is 
usually found. We cannot learn more than a certain amount 
from anv one group, but by each zoologist and botanist 
contributing his quota and the geologists adding theirs, 
we shall some day have a much clearer picture of how and 
where and why our different species originated and be- 
came distributed in the way they are. 
Perhaps you will ask, where does the field naturalist 
come into all this? He has a very definite part to plaA\ 
The taxonomist can only build on the information avail- 
able. The field naturalist has trained himself to observe 
nature and he may see differences in the field that are not 
apparent in museum specimens — differences in behavioiii' 
of animals, differences in environment, such as finding a 
toadstool under different kinds of trees and so on ; he can 
help by recording these things or telling the taxonomist 
about them. I have already pointed out that distribution 
of animals is bound xip with vegetation and climate. It is 
important to have the exact locality of a specimen, and 
the date to indicate its seasonal distribution. But locality 
does not tell us all we need to know. For instance on Mt. 
Tamborine quite different species might be found in the 
rain forest and in the eucalypt forest. The natural history 
