14 



THE BLACK HILLS BEETLE. 



Trees infested with partially to fully developed broods from the 

 latter part of August to the first of November, and during the period 

 of inactivity, are distinguished by numerous pitch tubes over and 

 entii'ely around the middle portion of the trunk and extending more 



or less toward the base and 

 top. The age of the pitch 

 tubes is indicated by their 

 relatively moist or dry con- 

 dition. A successful or vital 

 infestation will be shown by 

 the large number of pitch 

 tubes surrounding the entire 

 trunk, and also by their red- 

 dish color and general ap- 

 pearance. An unsuccessful 

 attack — from which the tree 

 will recover — is indicated 

 after the first of November 

 by a small number of smooth 

 whitish pitch masses scat- 

 tered about over the trunk, 

 confined to or toward the 

 base; their absence on the 

 middle to upper portion of 

 the trunk or, if present there, 

 their failure to completely 

 surround it. 



Positive evidence as to 

 whether or not a green- 

 topped, pitch-marked tree is 

 infested by living broods is 

 determined only by cutting 

 into the bark at different 

 places, 4 to 8 feet from the 

 base. Tliis test should be 

 made during the inactive 

 period, when trees are being 

 marked for cutting. 



Soon after activity begins 

 in the spring, infested trees 

 are distinguished by a pale appearance of the foliage, followed by a 

 yellow or reddish brown color, as if killed by fire. 



Dead trees which have been killed by the Black Hills beetle but 

 are no longer infested by living broods are distinguished during the 

 summer, fall, and winter by the old dry pitch tubes on the bark and 

 the dark reddish brown or ''black-topped" condition. The only 



Fig. 4.— Work of the Black Hills beetle: a, pitch tubes on 

 surface of bark, much reduced; 6, same, two-thirds 

 natural size. (Author's illustration.) 



