THE GENUS DENDROCTONUS. 
99 
but that it is necessary to reduce its numbers beyond the power of 
doing harm. 
The removal of the infested bark from at least the lower half of 
the standing trees offers many advantages over felling the trees for 
the purpose of barking all of the trunk. More insects can be destroyed 
in the standing trees within a given time and the barked standing 
timber may be left standing until suitable facilities can be provided 
for its utilization; thus, if necessary, all of the specified time for the 
destruction of the in- 
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sects may be devoted 
exclusively to the re- 
moval of the bark. 
The barking of newly 
attacked trees in Au- 
gust and September is 
not to be recommended 
for this species. Trap 
trees are of little or no 
service in combating it 
and continued timber- 
cutting operations ap- 
pear to have little or 
no influence in check- 
ing its ravages on liv- 
ing timber. 
Recent reports of 
conditions in the vicin- 
ity of Colorado Springs, 
where a large percent- 
age of the infested tim- 
ber was barked in 1905 
and during the winter 
and spring of 1906, in- 
dicate most successful 
and satisfactory re- 
sults. (See also other references to successful control, pp. 36-38.) 
The depredations in the Black Hills have been so extensive that 
little or nothing has been accomplished toward the control of the 
beetle, owing to lack of sufficient funds and other facilities for adopt- 
ing the radical measures necessary to accomplish anything of im- 
portance. 
(For additional information, see Bulletin No. 56, Bureau of Ento- 
mology of which the above is a partial revision.) 
Fig. 58.— Removing bark from base of trunk of standing tree with 
special barking tool, to destroy broods of the Black Hills beetle. 
(Original.) 
