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When the great scourge of locusts took place in Africa, and 
later on in America, Cyprus, and even in our own southern 
colonies, and, although the plague is of ancient origin, little 
was hitherto known of its life-history. Nowadays, however, 
the inhabitants of these hot countries have been able, by a patient 
and exhaustive study of these terrible insects, in many instances 
to be partially successful in coping with what would appear to 
have been a singularly hopeless task. It was found that there 
were two special periods at which they could be successfully 
attacked, viz., when in the egg stage; and, secondly, when in 
the newly-hatched or “ hopping” stage; the former being accom- 
plished by the collecting of the eggs, the authorities paying the 
collectors so much per bushel for same. The second plan consists 
in driving the young locusts, which were found by observation to 
be travelling always in the one direction. (I have had a rough 
sketch made of the latter plan from a photograph taken by a 
friend who took part in the locust destruction in Algeria. This 
plate I have brought for your inspection.) When tke young 
locusts are hatched they travel for a few days in a circle, and 
after they have obtained sufficient strength they commence their 
onward march in one direction. During this march they eat up 
every living plant which they can manage to digest. They have 
a wonderful appetite, and when in the winged state will devastate 
the whole vegetation of a country in no time. 
The screens as shown in the sketch, also in the model, often 
extend for a hundred or more miles over mountains and rivers ; 
and where labour is of little value the number of locusts destroyed 
by means of these screens is simply beyond all attempt at caleu- 
lation. 
In Australia, however, I am afraid that until the interior 
becomes more settled, and owing also to the comparatively high 
price of labour, an attack on the locusts on such an extensive 
scale as in the countries before mentioned would be well nigh 
impossible. 
At present we know a good deal concerning the life-history of 
these pests, and, partly for the purpose of refuting a statement 
that our Department of Agriculture were too late in taking action, 
I obtained freshly-deposited eggs and had them hatched artifi- 
cially. After making allowance for difference in temperature, &c., 
I found that we had nearly two months in which to attack them 
before they assumed the winged stages. These experiments, 
which I undertook principally for the defence of the Department, 
and partly for my own information, conclusively disproved the 
assertion that the Department had been dilatory in the matter, 
and also proved that it had done its best to induce the settlers to 
band together for the destruction of this terrible enemy. 
