34 
JOURNAL OF ECONOMIC ENTOMOLOGY 
[Vol. 13 
has more to recommend it, and the writer believes that such a plan 
may be evolved by a study of disease among the wild animals, with the 
end in view, of eradicating from any area concerned, those rodents or 
other animals which permit the disease to perpetuate itself. Such an 
investigation has been carefully planned, and a mass of circumstantial 
evidence already at hand indicates the possibility that the rodents or 
other animals which it may be necessary to exterminate will be very 
few in number. If this be so, the work will eventually resolve itself 
into a systematic campaign against certain species of animals, and 
will be aimed at the actual source of the disease rather than at the 
control of the transmitting agent, a long process at best, desirable 
though it may be. Such a program would have much to recommend 
it over the present system of control,—it would be more rapid, more 
effective and less expensive; it would eliminate features of the present 
system which are a source of constant irritation to a certain class of 
residents, and under some conditions, the reduction of ticks would be 
fully as marked as under the present system. 
Data Concerning Habits of Dermacentor venustus Banks 
In spite of time which has been devoted to the study of the habits of 
the tick, the writer feels that knowledge of the latter is limited, and 
that additional study would reveal points of value. Our knowledge of 
larval and nymphal habits, in particular, is extremely meagre, and 
those of the adult tick are by no means well known or understood. 
The remainder of this paper, therefore, will be devoted to the presenta¬ 
tion of a few points which the work of the past few seasons has 
brought out. 
Tick Migration. —It has always been supposed that the move¬ 
ments of the adult spotted fever ticks were of very limited extent, but 
while carrying on studies in eastern Montana in 1917, conditions were 
encountered which led the writer to believe that such was not the case. 
Subsequent observations have confirmed this opinion. Conditions 
which first suggested the idea of tick migration were found in a hilly 
area, cut by narrow valleys from which still narrower much-branched 
coulees extended back into the hills on either side. The floors of the 
coulees varied from a few feet to several hundred feet in width, and in 
the middle was always a rather narrow draw which remained green 
and moist until late in the season. Each side of the floor gave way to 
a short and usually steep slope surmounted by sandstone rimrocks. 
Weathered rocks from the cliffs had accumulated at their bases and 
on the slopes below. In the clefts of the rimrocks and among the 
fallen rocks, deer mice, chipmunks, pack rats and cottontail rabbits, 
