THE WESTERN riNE-DESTR()YIN(i HAKKBKETLK. 27 



is iniulc lartijor to accommodiitt" thesizeof the body. I lavMiijj reached 

 the outer hark, it hollows out an oval space or pupa case, in wliich to 

 go throuijli its transrornuitions. 



NATURAL ENEMIES. 



Larvic of the |)rcdaceous hectics of the ^enus C'lerus, which are 

 known to prey u])on Dendroctonus larvsp, were quite common in and 

 under the hark of tiie infested trees, and they doubtless help to some 

 extent in keepinjjj down the numbers of the barkbeetles. 



Birds contribute their part also in destroying larva* and i)upa\ The 

 work of woodpeckers was found upon most of the trees which had 

 been killed by I), hrevicomis, and these birds had evidently destroyed 

 a large percentage oi the insects in some of the trees, 



METHODS OF COMBATING THE INSECT. 



FIRST RECOMMENDATIONS. 



The following information and recommendations relating to this 

 insect and methods of preventing losses from its ravages were conveyed 

 by Doctor Hopkins to Mr. K. M. Hoover, or Boise, Idaho, manager of 

 tlie Payette T.iuuber and Manufacturing C\uiipany, in a letter dated 

 January L'o, 1!)06, and afterwards published, with Mr. Hoover's rejily. in 

 a local newspaper. 



Our special field agent, Mr. J. L. Webl), has .submitted his report on forest insect investi- 

 gations in the vicinity of Ccntcrville and Smiths Ferry, Idaho, during the past summer, and 

 It will interest you no doubt to know that the insect which is primarily to blame for tlie death 

 of pine trees was located and thoroughly studied by him. 



He found that the broods of the destructive species pa.ss the winter in the grub state in the 

 bark of trees wliich died during (he late summer and fall and that they do not transform to 

 the V inged form and emerge uiitilafler the 1st of .May. Therefore the met lu)d of combating 

 the pest IS simply to <ut tiie mfested trees any time between the 1st ol October and the 1st of 

 .May and to remove the bark from the main trunk and burn it. 



It is nece^ssary to burn the bark in order to kill the broods of this in.s<'ct, lu'cause they 

 <K"cupy the intermediate portion between the inner surface and the outer scale portion; 

 hence the drying of the removed bark will not kill them as it would if they occupied the 

 inner moist portion. 



The infested trees can be loruted ( 1 ) by the yellowish and light reddish brown color of the 

 foliage; (2) by cuitmg mto the Imrk as high up on the trunk as a man can reach with an a.\ 

 to determine whether the middle portion of the bark is infested with the small white grubs, 

 which are about three-sixteenths of an inch long. If tlu'seare found, it will Im- <'onclusive 

 evidence that the tree has been killed by the beetle and is infested with its broods. It must 

 be remembered that there are hundreds of other kinds of in.s«'cts which occupy the innrr |>or- 

 tion of the bark and wood of such trees, but none of the smaller ones pa.ss the winter in the 

 outer bark. • * • 



Perhaps the most important thing for you to do as a preliminary to any definite action vou 

 may take in the matter is to have a number of intelligent crui.sers make a survev of your 

 holdings for the purpose of locating the principal sections in which trees have die«l during the 



