THE BLACK HILLS BEETLE. 



(Demlroctonus panderosne « Hopk.) 



INTRODUCTORY. 



The object of this bulletin is to give additional information on 

 the distribution, life history, habits, and methods for the control 

 of the Black Hills beetle, based on further investigations by the 

 writer and his field assistants, and information through correspond- 

 ence with forest officials and others. 



It is now known that this beetle occurs in the eastern sections of 

 the Rocky Mountain region from the Black Hills of South Dakota 

 to northern New Mexico; and there is evidence that its distribution 

 extends westward into Utah and northern Arizona. 



It attacks and kills the western yellow or bull pine (Pinus pon- 

 derosa) and the white spruce (Picea canadensis) in the Black Hills 

 of South Dakota; and the western yellow or bull pine, the limber 

 pine (Pinus flexilis), and the Engelmann spruce (Picea engelmanni) 

 in the Pikes Peak region. 



Wherever this insect is found in abnormal numbers its depreda- 

 tions on living timber are more or less extensive. It has killed 

 between 700,000,000 and 1,000,000,000 feet of timber in the Black 

 Hills Forest Reserve, and is also demonstrating its destructive 

 powers in central Colorado and New Mexico. 



The method for its control recommended by the writer and 

 adopted in the Black Hills and Pikes Peak region has been suffi- 

 ciently tested to show that it is both practicable and effective, and 

 that, under proper management, a forest can be protected at a 

 moderate expenditure, or almost without cost where there is a 

 market for the timber. 



HISTORICAL REFERENCES. 



Probably the earliest published information on the destructive 

 work of tins insect is that by Prof. H. S. Graves, 6 in which he refers 

 to the dying pine timber in the Black Hills of South Dakota. He 

 stated that the patches of dying and dead timber are usually rec- 

 tangular in shape, following the tops of the divide or ridges and 

 running lengthwise up and down the slope, and that this injury was 

 probably caused by bark-boring insects of a species of Scolytid®, 



« Family Scolytidw. & Ninth Rept. U. S. GeoL Surv., Pt . V, p. 87, L897 98. 



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