DISTRIBUTION. 15 
drugs. In spite of this it has been found that the only hope for the 
eradication of the disease, or even for practical control, is in the 
destruction of the ticks. Inasmuch as no means of preventing or 
curing spotted fever are known, the importance of attacking the ticks 
is much greater than in the case of splenetic fever. The situation is 
also analogous to that brought about by malaria and yellow fever, 
which, as is well known, are transmitted by certain mosquitoes. The 
control of these diseases in all parts of the world has practically re- 
solved itself into a warfare against the mosquitoes. 
These considerations seem to make it very evident that the logical 
course to follow in the eradication or control of spotted fever is the 
elimination of the tick. The problem becomes purely an entomologi- 
cal one. Under these circumstances, it is most fortunate that certain 
feasible and economical means of eradication, first outlined in a 
rather general way by Dr. Ricketts, have been placed upon an exact 
and certain basis by the recent investigations of the Bureau of 
Entomology. 
DISTRIBUTION OF THE SPOTTED-FEVER TICK. 
As is shown in the accompanying map (fig. 1) the range of the 
Rocky Mountain spotted-fever tick extends throughout the north- 
ern part of the Rocky Mountain region across the Great Basin to 
the eastern edge of the Cascade Range. The southernmost limit of 
the tick is in the northern edge of Xew Mexico. Although the dis- 
tribution of the species in Canada has not been determined, there 
is little doubt that it extends over the southern half of British Colum- 
bia and the western portion of Alberta. However, only one accurate 
record of the occurrence of this species in Canada has been made, 
namely, by Dr. H. G. Dyar, who captured two female >pecimens 
at Kaslo, British Columbia, in 1003. 
"While infestation occurs throughout large portions of Montana, 
Idaho, Washington, Oregon, Nevada, Utah, Wyoming, and Colorado, 
comparatively small areas in Xew Mexico and California are infested. 
The tick probably occurs throughout the entire Black Hills region in 
South Dakota and Wyoming, although but one collection has been 
made in that region. 
Naturally there is no uniformity in the abundance of the tick 
throughout the territory in which it occurs. 
Our knowledge of the local occurrence of the tick throughout the 
Western States is not sufficiently complete to enable as to make 
definite statements as to areas within the whole infested region in 
which comparatively few ticks are to be found. We do know, how- 
ever, that certain sections of the country which are unfavorable for 
the development of the species are only slightly or not at all infested. 
