38 LIFE HISTORY OF NORTH AMERICAN TICKS. 
must be recorded in connection with the thermometric readings, as 
all life processes when the ticks are off the host appear to be affected 
by variations in temperature. Our out-of-doors records are based 
upon temperatures registered by the thermograph shown in Plate IT, 
figure 1. Those indoors were based on a similar thermograph kept 
in the room with the ticks and regulated by standard thermometers. 
In determining the life cycle of ticks that attach to small animals, 
such as dogs, rabbits, squirrels, fowls, and others, a satisfactory 
arrangement found has been the use of a cage made of wire of about 
1-inch mesh, permitting the ticks to drop through into a pan beneath. 
(See Pl. I, fig. 4.) This cage, made with a wooden frame, should have 
the joints set in white lead or putty in order to eliminate all pos- 
sible hiding places into which the ticks might crawl for protection. 
Nails inserted in the frame serve as posts, preventing the ticks from 
crawling back to the cage. In the pan or tray under the cage may 
be placed strips of paper, beneath which the ticks will crawl. Some 
thick and absorbent paper, such as blotting paper or pressing paper, 
should be placed in the bottom of the tray or pan to absorb the urine. 
When this is used it is not necessary to eliminate succulent food from 
the diet of the host animal. It has been the practice to place a ring 
of white axle grease about the rim of the pan or tray to prevent the 
escape of any of the ticks which have dropped. Another and more 
satisfactory way of preventing their escape is by setting this pan or 
tray in a larger one filled with water. When the examinations are. 
made the tray can be removed, the ticks collected, and the cage 
cleaned with little difficulty. The plan of this tray was first sug- 
gested to the writers by Prof. Lounsbury and is similar to that 
which he has used. A more satisfactory cage than the one just 
described for use with small hosts, such as guinea pigs and rabbits, 
has been made by taking two wire desk trays or baskets and fastening 
them with rubber bands, one bottom side up over the other, as shown 
in Plate I, figure 1. The principal advantage of this kind of cage 
over the other is that places for hiding are practically eliminated, 
thereby allowing quicker examinations. Though the cages may be 
made of other coarse-mesh wire screen, the desk trays are to be pre- 
ferred. To prevent the animals from shaking the ticks across the 
moat an 18-mesh wire-screen band is placed around the cage, with its 
base set in the tray and the top extending a few inches higher than 
the cage. 
In order to keep the ticks upon or near the host while attaching 
and to prevent their escape, a canvas cage was used. A square 
wooden frame was first made, to which the canvas was fitted just 
tight enough to permit of the removal of the frame so that the canvas 
bag could be inverted and readily cleaned. 
