i6 
fever in cattle ; if, within recent years, it had been ascertained 
that poultry, when imported, came only from places where the 
fowl-tick (Argas) did not exist, our fowls would not now be 
suffering so frequently from the disease transmitted by these 
parasites ; swine-fever might have been similarly evaded. 
The exotic animal invasions so far discussed have been 
designed invasions and have not transgressed the limits of control. 
There are, however, some which, though originally intentional, 
have become of great economic importance from the vast numerical 
increase of their members. The rabbit is a case in question. 
Originally let loose in the hope that they would breed and form 
objects for sport as well as furnish something for the table, 
they have multiplied beyond all conception, having so few enemies 
with which to contend and such a genial climate to live in. Al- 
ready have they swept almost across the continent and have caused 
losses of man}' millions of pounds. Not only is there the loss 
from herbage devoured, but a still further one from the disturbance 
of the soil, a very serious matter especially in sandy country. 
The inexcusable introduction of the fox for sporting purposes 
has led to his rapid multiplication in parts of Victoria, South 
Australia, etc., and the loss of many sheep. Cats have become 
wild and, near Perth for instance, fierce and powerful in build, 
feeding on the native birds and smaller animals and rabbits where 
these are present. 
The introduced rats {M us norwegicus, the Norway Rat, 
and Mus alexandrmus, the old English “ black rat ”) seem not 
to have extended beyond man’s more immediate surroundings. 
The dominant rat in' Perth is the sociable black rat, the larger 
Norway rat being only hitherto obtained from the neighborhood 
of the wharves at Fremantle and Perth. It is otherwise in 
Sydney, however, where both are found together in the town. 
These rats have brought with them several species of fleas, of 
which some will bite man when their original host is absent 
( e .g . has died). By this means another exotic disease, the plague, 
introduced by the rats, is communicated to man. 
The sparrow, the starling, the goldfinch, the blackbird, and 
the Indian mynah have all come to stay. Some of these eat much 
grain and fruit, while all tend to drive away and usurp the place 
of our beautiful interesting and useful native birds. I am glad 
to say that the only foreign bird I have seen flying free in Western 
Australia was a single chaffinch or green-finch. 
I need hardly refer to such exotic insect pests as the bed-bugs, 
the fruit-fly and the codlin-moth. The stable-fly ( Stomoxys 
calcitrans) is a comparatively recent arrival in Perth and is 
ominous, not only on account of its painful bite, but also because 
it is a known transmitter of certain trypanosome diseases such as 
surra. Horse-bots naturally came with horses. 
