70 
Biology of Ixodidae 
frequently the ticks could be readily found after they had dropped from 
the host—sheets of white paper, frequently renewed, have usually been 
laid upon the floor of the cage immediately beneath the grating upon 
which the host animal rests. The cages were searched for ticks at least 
once daily whilst gorged specimens were dropping from their host, 
and their numbers, etc. were on each occasion noted immediately. 
In cold weather, before infesting the host, it is sometimes necessary 
to activate hungry ticks by warming them in a thermostat, for cold 
renders them torpid. After all, as Stockman has pointed out, warming 
the ticks in this manner is but to simulate conditions which may arise 
in nature when a warm-blooded animal rests upon tick-infested ground 
in cool weather and activates the ticks through the warmth radiating 
from its body. 
Maintaining ticks apart from the host. When gorged larvae and 
nymphs had been collected from the floor of the cage or elsewhere, they 
were placed in wide-mouthed bottles or inverted bell-jars containing a 
layer of dampened earth an inch or so in thickness. The surface of 
the earth was pressed smooth, and folded pieces of Alter paper were laid 
upon it for the ticks to creep upon. The aperture of the vessel was 
guarded with fine-meshed muslin held in place by rubber bands and 
string or thread wound around the vessel and knotted. The ticks, when 
necessary, were periodically transferred to clean quarters. Gorged 
females were usually placed singly in wooden pill-boxes bearing 
numbers and dates, the boxes resting on a layer of slightly dampened 
earth in an open jar. After oviposition was nearly completed, the 
egg mass laid by each tick was placed in a tightly corked tube con¬ 
taining slightly dampened filter paper. In some cases isolated females 
were allowed to oviposit in similar tubes and their bodies were 
removed after death, the eggs remaining undisturbed in the tube 
during metamorphosis. It is best to moisten the filter paper or earth 
with 15 "/o NaCl solution for the first time, adding simply water after¬ 
wards if more moisture is needed. The addition of salt is a safeguard 
against moulds which formerly were a source of much trouble to us. 
When dealing with active larvae it has been found at times con- 
venient to keep them, both before and after hatching, in wide-mouthed 
bottles closed by a cork or glass stopper covered with filter paper. By 
moistening the filter paper which protrudes between the stopper and 
the mouth of the bottle a slight amount of water may be allowed to flow 
in and dampen the filter paper which covers the stopper within the 
bottle. In all cases an excess of moisture must be avoided ; at times it 
