1 Ava., 1901.] QUEENSLAND) AGRICULTURAL JOURNAL. 263 
A female may lay 0 gr. 10 of eggs; hence, in 1 centigramme, I have 
counted 608, which makes a total Jaying of 6,0U0 eggs. The more the tick is 
gorged with blood, the more eggs she lays; but even when she is scarcely 
swollen, she may lay some hundreds. 
The hatching of the eggs began, in the experiment I am relating, on 26th 
April, or twenty-one days after the laying. 
The eggs, at first reddish and transparent, become gradually darker and 
opaque; a few.days before the hatching they acquire a greyish tinge. Then 
the young larve begin to come out, often dragging after them a portion of the 
egg-shell. These larve remain together for from twenty-four to forty-eight 
hours on the mass of eggs ; some hatched, some not. Then they begin to climb 
the walls of the mud in which they were enclosed, or over blades of grass, 
when they gain their liberty, scattering in their course the remains of the 
egg-shells. 
As we have seen, twenty-one days are needed for the complete evolution 
of the tick. If we add five days for laying and the twenty-one days which the 
eggs take to hatch out, we see that complete generation requires, at least, 
forty-seven days. 
But, as in the case of a host of parasites, there are considerable variations 
in the duration of the evolution of the tick. -Thus— 
I have been able to preserve, at a temperature of + 8° to + 15° C., for two 
months, a tick gorged with blood, without its beginning to lay. When I afterwards 
subjected it to a higher temperature—up to + 30° C. - she laid fairly regularly. 
The eggs themselves can be preserved for a still longer time; I have kept some 
in the ice-chest for from four to six months without their losing their vitality. 
This property enables them to live during winter. 
As regards the hexapodian larve, which have been represented as being 
able to live for a long time away from their host, in reality they are less 
resistant than the eggs. Usually they die after three weeks; rarely do- they 
live for one or two months, whether at liberty in the grass or enclosed in 
bottles. On the contrary, at a low temperature, + 4° to + 10° C., they may 
be kept alive much longer. 
In the pastures infested by titks it is ‘easy to follow up the young 
ones. After they are hatched, they crawl about for some twenty-four hours on 
the eggs and remains of shells, which they often drag after them ; then they 
climb to the tops of the grass, where they may be seen in little clusters, 
constantly waving their feet in the air in the hope of hooking themselves on to 
some favourable host. 
EXPERIMENTS IN PROPAGATING BOVINE MALARIA BY 
MEANS OF TICKS.* 
The experiment, which consists in taking ticks from a dead animal or from 
one affected with bovine malaria to remove them to another, is difficult to 
manage, because these parasites are so firmly fixed in the skin that when they 
are detached they leave either the whole of the mandible or part of it behind. 
Still, if care be exercised by removing the ticks with the help of a needle, they 
may be got off intact. Under these conditions I have seen them again attach 
themselves, even when they have already undergone the first and even the 
second sloughing. But the number of ticks which one can transplant is so 
restricted that there is small chance of communicating the disease. or my 
part, I have never seen any symptom of malaria supervene amongst the cattle 
on which [ had thus transplanted some ten ticks. 
Smith and Kilborne infested paddocks with ticks which, until then, had 
been free from them, either by scattering a great number of completely 
developed females or by placing cattle in them, sick or well, carrying ticks, and 
* When the ticks are very numerous on animals, they cause the latter much suffering. The 
cattle become emaciated and occasionally die. I have seen cattle which were usually very 
docile, on which I had several times placed ticks, become excited and dangerous the instant they 
divined my intention to infect them again. : 
