84 Gerald F. Hill : 



Following Swingle, the present writer marked some young: 

 '' ticks " by stickinig a very small piece of coloured paper on the- 

 dorsum of the abdomen, others with coloured adhesive substances- 

 and stains. None of these methods, however, was sufficiently per- 

 manent to be of any service. The following method employed suc- 

 cessfully by Swingle was then tried : — A short piece of silk thread 

 was separated into its three component strands and tied around 

 the young *' ticks " between the thorax and abdomen. The ends 

 were then snipped off close to the knot and the "ticks" were- 

 liberated on a lamb previously freed of '* ticks." For this purpose- 

 young '' ticks " wliich had been fed were employed, as they were 

 kps liable to be damaged tlian very young ones. In most cases the- 

 marked " ticks " found their way to the surface of the wool and 

 remained there until they died. In others they remained in the- 

 fleece, but did not thrive, and ultimately died. Sw^ingle remarks 

 (p. 21), " . . . if a dozen female ' ticks ' be placed in the w^ool 

 within a circle having a diameter of two inches, the following day 

 they will most generally be found very near that area, at least 

 within a radius of three or four inches." This has not been the 

 present writer's experience here. Even during the winter months 

 the young " ticks " especially showed a very noticeable inclination 

 to wander freely and rapidly, even when encumbered as described 

 above. This fact accounts in a large measure, if not entirely, for 

 the Avriter's want of success in these experiments. 



As a last resort a lamb was shorn and freed of '' ticks " after 

 which sixteen young " ticks " were liberated in the fleece (January 

 12th). The history of these " ticks "up to January 20th is 

 recorded in Experiment No. 4, page 81, where it will be seen that 

 only nine of the orijginal sixteen '' ticks " could be found at the end 

 of thirty-nine days. Of those found only three were females. It 

 was intended to keep these nine *' ticks " under observation with a 

 view to ascertaining how long they would live and how many pupae 

 each would extrude during its life. As stated on page 81, two of 

 the three ''ticks" had already extruded three pupae each, the 

 third contained a larva nearly ready for extrusion. On February 

 20th these three *' ticks " were liberated on a lamb previously shorn 

 and freed of these parasites. On the following day the " tick " 

 containing the large larva w^as found dead. On the forty-eighth 

 day (March 1st) one pupa was found, but one of the two remaining- 

 females could not be accounted for. After two more unsuccessful 

 attempts to find the missing " tick " the experiment w^as aban- 

 doned. 



