30 
THE KOCKY MOUNTAIN" SPOTTED FEVER TICK. 
fested. Among the other mammals which are of considerable impor- 
tance as hosts of the immature stages are the large chipmunk, the 
woodchuck, snowshoe rabbit, rock squirrel, wood rat, white-footed 
mouse, and meadow mouse. 
Our knowledge of the tick hosts" in the valley was greatly increased 
by the cooperation of the Biological Survey of this department. 
Messrs. Howell and Birdseye, of the Survey, were located at the 
camp laboratory and made extensive collections during 1910. This 
work was continued in 1911 by Mr. Birdseye. Table V furnishes a 
list of the wild mammal hosts of this tick. It includes all the records 
of the Biological Survey, 1 as well as a number made independently by 
Mr. King, of the Bureau of Entomology. The mammals are listed in 
the table according to their relative importance as hosts of the im- 
mature stages. It is especially worthy of note that among the wild 
mammals which act as hosts for the adult stage the mountain goat 
and brown bear are the only ones which were found to have ticks 
upon them which were engorged sufficiently to deposit eggs. 
One hundred specimens of the birds commonly found in the valley 
were examined and found to be free from ticks. 
Table VI. — Host animals on which Dermacentor reiiusius in the adult stage 
has been found. 
ON DOMESTIC ANIMALS AND MAN. 
Common names. 
Scientific names. 
Approxi- 
mate 
number 
of hosts 
exam- 
ined. 
Approximate number of 
ticks collected. 
State of engorgement 
Males. 
Females. 
Total. 
of females. 
Ox... 
200 
800 
9 
100 
5 
10 
900 
1 
2,000 
2,500 
9 
14 
22 
IS 

2 
400 
1 
2,000 
2,500 
5 
17 
32 
20 
4 
4 
400 

4,000 
5.000 
14 
Unengorged to fully. 
Do. 
Equus caballus 
Equus asinus 
Equus asinus X cabal- 
Ins. 
Do. 
31 Do. 
54 
38 
4 
6 
800 
1 
Unengorged to one- 
half. 
Ud en gorged to three- 
Dog 
Canis familiar's 
Goat 
fourths. 
Unengorged to 
Hog 
slightly. 
Homo sapiens 
Felis domesticus 
third. 
Unengorged to one- 
fourth. 
Unattached. 
Domestic cat 
ON WILD ANIMALS. 
Mountain goat . 
Coyote 
Brown bear 
Jackrabbit 
Woodchuck 
Snowshoe rabbit . 
Wildcat 
Badger 
Oreamnos montanus 
Canis lestes 
Ursus americanus . . . 
Lepus sp 
Marmota flaviventer 
Lepus bairdi 
Lynx uinta 
Taxideataxus 
3 
150 
150 
300 
1 
15 
16 
31 
4 
9 
13 
15 
3 
G 
9 
51 
2 or 3 
2 or 3 
5 
2 
1 
3 
1 

1 
21 

1 
Unengorged to fully. 
Unengorged to 
slightly. 
Sl ; ghtly to one-fourth. 
Slightly to one-sixth. 
Slightly. 
One-seventh engorged. 
1 See United States Department of Agriculture, Biological Survey, Cir. No. 82. 
2 Dead. 
