Insects and Parasitic Diseases* 83 



Summapy and Observations. 



It will be seen from these expeiiiiients tliat the young' Louse-tiy or 



'*' tick " may reach maturity during the early winter thirteen days 



,after its emergence from the pupa. In one experiment (No. 3, p. 80) 

 the young " ticks " were kept very close together, and therefore had 

 an opportunity of copulating as soon as they were sufficiently 



•developed. Copulation took place on the fifth day after tlieir 



.emergence. 



In two other experiments (Nos. -t and 5) carri^ed out in mid- 

 summer the young "ticks" copulated on the eleventh and four- 



.teenth days respectively, and reached maturity, i.e., extruded the 

 first pupa, on the twenty-first and twenty-third days respectively. 



Jn these two experiments the few " ticks " under observation had 

 access to all parts of the host's fleece, and appeared to be con- 

 stantly moving from one part of the body to another. Under these 

 conditions the chance of early mating would be greatly reduced, and 

 it is believed that this fact alone accounted for the long period 



• elapsing between their emergence and the deposition of the first 

 pupa as compared with the period ascertained in Experiment No. 3, 

 in which the young "ticks" were kept close together. Swingle 

 (1913, p. 16) found that young " ticks " marked with a silk thread 

 tied around the constriction between the body and thorax and then 

 liberated on the host copulated on the fourth or fifth day during 

 the winter, when the average maximum' temperature was 27.3° and 

 the average minimum temperature was 7.2.°. He observes also 

 (p. 23) that young male and female " ticks " are capable of copu- 

 lating when three days old. 



The same investigator (page 18) found that the young female 

 "tick" required a minimum period of fourteen days in which to 

 reach maturity, but he considered that the period might possibly 

 be reduced by carrying out experiments with thousands of " ticks.'" 



"3. To determine the length of life of the female. 



As previously stated, it was found impossible to keep the " ticks " 

 for any lengthy period Avithin a confined area upon the host; those 

 that were unable to escape soon perished. In one experiment (No, 

 3, p. 80) young " ticks " were kept for two weeks in an enclosed 

 area, but in all others they died or escaped within a week or less. 

 It was appart^nt theiefore, that some method would have to l)e 

 devised Avhich would allow the "ticks " a much frreater measuie of 

 libertv if the desired information was to be obtained. 



