30 THE ROCKY 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, snowshce 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,’ 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 venustus in the adult stage 
has been found. 
ON DOMESTIC ANIMALS AND MAN, 
Approxi-| Approximate number of 
mate ticks collected. 
sas number State of engorgement 
Common names. Scientific names. Giiosts oftifernales. 
exam- 
ined: Males. | Females.| Total. 
Ox rank ashok ome BOS TAWNUS te oe 200 | 2,000 2,000 | 4,600 | Unengorged to fully. 
HIOTSGe. cheach ace ces Equus caballus...... 800 | 2,500 2,500 | 5,000 Do. 
TASES Soe eee Equus asinus.....---. 5 9 5 14 Do. 
Male vee 2. = ze Se Equus asinusX cabal- 9 14 17 31 Do. 
lus. 
Sweep Eos. wee as os Ovis airlesaes 3 Ay 75 22 32 54 bee ees to one- 
half. 
1D Jaf eee pe ee es Canis familiaris...... 100 18 29 38 | Unengorged to three- 
fourths. 
ORG et ea ees ees Capra hireus. ...25. -. 5 0 4 4} Unengorged to 
slightly. 
HO. ie sh. 60s eee Sus serofac 2.5.5: 5. 10 2 4 6 ao to one- 
third. 
Man bets. choses Homo sapiens..-..---- - 900 400 400 800 ee aie to one- 
fourth. 
Domestic cat... ..-- Felis domesticus... .- 1 1 9 1 | Unattached. 
ON WILD ANIMALS. 
Mountain goat..... Oreamnos montanus. 3 150 150 300 | Unengorged to fully. 
Coyotet smite Canis lestes.........- 1 15 16 31; Unengorged to 
slightly. 
Brown bear........ Ursus americanus... 1 4 9 13 | Slightly to one-fourth. 
Jackrabbit......... Lepusispen.. sascsees 15 3 6 9 | Slightly to one-sixth. 
Woodehuck.......-. Marmota flaviveniter. BL], Dares 2or3 5 | Slightly. 
Snowshoe rabbit...| Lepus bairdi........- 4 2 1 3 | One-seventh engorged. 
MUA cat 2064.2 Liynswints.. 22. +562 2. 1 1 0 1 
adr. ots Su ee Taxidea taxus...-..- 4 21 0 1 
vee vee States Department of Agriculture, Biological Survey, Cir. No. 82. 
ead. 
