INSECT ENEMIES OF WESTERN FORESTS 185 
compass man, who is usually the chief of the party, runs an accurate 
compass line, paces the distances traveled, records data relative to 
trees marked for tre atment, constructs a map showing their location, 
and assists the spotters in the selection of the proper “trees for treat- 
ment. The two spotters cover strips on the sides of, and parallel to, 
the course of the compass line, find, blaze, and number the infested 
trees, and record whatever data are pertinent in regard to them. 
With a six-man crew there are two spotters on each side of the 
compass man, and the chief of the party follows behind the crew, 
working from side to side to assist in the proper marking of the 
Ficurb 88.—Ponderosa pines spotted for treatment in Black Hills beetle control, Kaibab 
National TYorest, Ariz. 
trees and to prevent any from being missed. Regardless of the or- 
ganization, the chief spotter is always responsible for the character 
of the work performed by his crew. 
The width of the strip and the number of men in the spotting 
crew are usually adjusted to the timber type, topography, and 
density of the infestation. In typical ponderosa pine stands a 
three-man crew, with each spotter covering a five-chain strip, is 
the standard practice. This width of strip in the open timber stands 
of this type permits the spotters to visit and closely examine not 
only the fading trees but all of those which look suspicious and a 
high percentage of the green trees as well. On the other hand, in 
dense lodgepole and white pine stands a one-chain strip is all that a 
spotter can efficiently cover, since it is necessary to look at the base 
of every tree, and a six- man crew has been found advantageous in 
