168 LIFE HISTORY OF NORTH AMERICAN TICKS. 
GEOGRAPHICAL DISTRIBUTION. 
(Fig. 14.) 
The type locality of this species is Soldier, Idaho. The distribu- 
tion of this tick has been rather accurately determined by the Bureau 
of Entomology working in cooperation with Prof. R. A. Cooley and 
numerous correspondents throughout the Western States. The tick 
has been found to occur from British Columbia southward to north- 
ern New Mexico and from the foothills of the Rocky Mountains in 
Colorado to the base of the Cascade Range in Oregon and California. 
It is very abundant in western Montana, and throughout Idaho, east- 
ern Washington, and Oregon, northern Utah, western Wyoming, and 
northwestern Colorado. A detailed statement regarding the distri- 
bution of this species has been published (Bishopp, 1911a). 
LIFE HISTORY. 
Observations on the biology of this tick have been published by 
Ricketts (1906, 1907, 1908) and by Cooley (1909, 1911). 
The egg (Table LX XVI). —The preoviposition period of this species 
varies from 5 to 17 days. One partially engorged female which was 
picked from a host March 24, 1910, had a preoviposition period of 25 
days. The temperature experienced by these ticks can not be given 
accurately, as the ticks were collected in Montana and mailed to the 
laboratory at Dallas. Females which dropped from hosts at the Dal- 
las laboratory showed a variation of from 6 to 14 days in their pre- 
oviposition periods. The shorter period was recorded on specimens 
kept at 66° F. and the longer on specimens kept at 79° F. However, 
preoviposition periods of 7 days were observed when the mean tem- 
perature was about 80° F. and when the mean temperature was 68° 
F. preoviposition periods as long as 14 days were observed. The 
period of deposition varied from 15 to 32 days. The maximum 
number of eggs deposited by a female was 7,396; the average of 11 
was 5,421.8. The individual which deposited the maximum number 
of eggs measured 16 by 11.5 by 6.1 mm. before deposition was begun. 
The number of eggs deposited by an individual is governed largely 
by its size. 
Females which were removed from a host when about one-fourth 
engorged have been found to deposit fertileeggs. Three females which 
measured 8 by 5.5 by 2 mm., 8.3 by 5.3 by 2 mm., and 8.5 by 5.5 by 
2 mm., began depositing on the fourteenth, tenth, and twelfth days 
after being removed from the host and deposited 211, 1,019, and 636 
egos, respectively. 
The minimum incubation period recorded was 16 days. This occur- 
red in the case of eggs deposited June 13, 1908, which experienced a 
mean temperature of 81.4° F. <A total effective temperature of 
614.75° F. was accumulated during this period. Ricketts states 
(1909a, p. 100) that in Montana eggs deposited in July hatch in from 
