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Third.—lIf it is desirable to girdle trees at other times during the 
summer and to utilize trap trees, these latter should be provided a week 
or more ahead of the girdling, and located on the banks of streams, 
ponds, or pools, where, at the proper time, they can be readily rolled 
into the water. 
Fourth.—Trap trees should never be provided unless it is quite cer- 
tain that they will be placed in the water or otherwise destroyed within 
two or three months after they are felled and infested by the insects, 
otherwise they may contribute to a greater multiplication of the insects 
and increased danger of serious injury to the girdled trees. 
The adoption and carrying out of these recommendations should be 
governed in each locality by the personal observations and experience 
of the operators, based on a study of the conditions resulting from trees 
girdled at different positively known dates or times of year, and also on 
a study of the evidences of infestation by the pin-borer in the girdled 
trees and in the logs, stumps, slash, etc., of cypress, gum, and other 
trees. These evidences of infestation consist of the greater or less quan- 
tities of fine, whitish boring-dust on the bark and around the base of the 
trees and stumps, under the logs, etc., the work of the girdled-cypress 
pin-borer and its class being distinguished from that of the sapwood 
borers by the prevalence of short cylindrical sections of adhering dust 
expelled from the holes. 
For more detailed information on the habits of wood-boring insects 
and the character of injuries caused by them in standing and felled 
trees, lumber, etc., the reader is referred to the Yearbook of the United 
States Department of Agriculture for 1904, pages 381 to 398. 
Approved : 
JAMES WILSON, 
Secretary of Agriculture. 
WASHINGTON, D. C., December 19, 1906. 
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