44 THE EOCKY MOUNTAIN SPOTTED FEVER TICK. 
Nevertheless, if the number of these animals can be reduced, it will 
have an important effect in lessening the number of ticks present. 
In addition to this reason for control, the rodents are pests of con- 
siderable importance. Their extermination from the valley, if pos- 
sible, would amply repay the residents in the preventing of losses 
to their crops. 
The conditions existing in the brushy land or " slashings " along 
the edge of the valley are especially favorable to the tick. Not only 
is shade and protection furnished, but the presence of the timber 
furnishes the rodent hosts f avorable opportunities for multiplication. 
In this way the presence of the brush has an important bearing upon 
the abundance of ticks. If the land should be cleared, the ticks 
would be considerably affected. Clearing the lands will, of course, 
increase their value and make possible their planting in orchards or 
other crops without loss of time when the fever tick shall have come 
under subjection. 
For a full list of the mammals found in and around the valley and 
for methods for their extermination the reader is referred to Circu- 
lar 82 of the Biological Survey of this department. 
It is not considered necessary to have these supplementary means 
of control supported by funds raised for the main operations. The 
work of destroying rodents and of clearing the brush lands should 
be conducted by residents on their own initiative. The matter 
should be sufficiently explained and the residents should by every 
means possible be encouraged to undertake the work. 
NECESSITY FOR EXPERT SUPERVISION. 
In the work of controlling the spotted-fever tick in the Bitter 
Root Valley it is absolutely essential that expert entomological 
supervision be provided. Since the whole campaign depends upon 
a knowledge of the habits and life history of ticks it must be evident 
that the work must be in the hands of persons who are thoroughly 
familiar with the subject. Among the many reasons why this expert 
supervision is necessary are — 
(1) The proper time to begin and to discontinue the dipping or 
oiling must be determined. This will depend upon the seasons and 
the time when the tick begins to develop in the spring. Unless men 
are at hand to determine when to begin and when to end, much un- 
necessary work might be done or, what is worse, many ticks might 
escape. 
(2) It is necessary to be certain that the dipping solution is kept' 
up to a strength sufficient to kill and to see that the dipping is prop- 
erly done. The test of the strength of the solution should be con- 
ducted by experiments the results of which could be interpreted 
safely only by experts. 
