F. C. Bisiiopp and H. P. Wood 
165 
Life History. 
As previously stated in the introductory remarks, this tick remains 
on the host for both moults. 
Oviposition takes place in the usual manner in the most pro¬ 
tected place available to the female after dropping off its host. The 
duration of the oviposition period varies greatly, according to the tem¬ 
perature, and, to some extent, the humidity, following the dropping 
of the engorged female. The shortest preoviposition period which we 
have observed at Dallas, Texas (see Tables I and III) was seven days, 
and the longest 134 days. The minimum record was made on a female 
collected in Montana on April 15, 1910, and received at Dallas, 
April 22, hence the temperature experienced by this tick during the 
first four days of its preoviposition period is not known. 
The rate of oviposition fluctuates considerably with changes in 
temperature. The greatest number of eggs which we have observed 
to be deposited during a single day is 393. The period of egg laying 
varied from 19 to 42 days. The number of eggs deposited by a single 
female ranged from 1455 to 4411 in the nine counts made (see Table I). 
The last three records given in this table were made on ticks kept in 
an incubator at a mean temperature of about 90° F. The number of 
eggs deposited is usually in proportion to the size of the engorged tick. 
The length, width and thickness in millimetres of some of the ticks, the 
deposition of which is recorded in Table I, were as follows : Mo. 3, 
11 x 81 x 51; No. 4, 115 x 8 5 x 61; No. 7, 10’6 x 7'9 x 4'8 ; No. 8, 
1T4 x 8'5 x 51 ; No. 9, 1T2 x 7 - 9 x 4 - 6. The length does not include 
the capitulum. The females die within one to 30 days after completing 
oviposition. 
The eggs of this tick are slightly smaller than those of the other 
American species of this genus, the size ranging from 452 by 373 
microns to 488 by 387 microns. They are smooth and shining, yellowish- 
brown in colour and ovoid in outline. They are coated with a moderate 
amount of the viscid secretion supplied by the vesica biloba. 
At Dallas, Texas, the incubation period has been found to vary from 
33 to 71 days. Most of our figures on this point are determined by 
computing the time from the beginning of deposition to the first 
hatching of larvae in the entire mass of eggs deposited by one female. 
All of the records given in Table II were made on ticks kept on moist 
sand in the laboratory. The length of the incubation period is closely 
related to the mean temperature during hatching. In the northern 
