INSECT DKPREDATIO.NS KN ,\()KTII A.M KKK AN F( jHKSTS. 59 



This species caused the death of a very hirge percentage of the ma- 

 ture spruce over an area of thousands of square miles. In the aggre- 

 gate many billions of feet of the best timber were destroyed. The 

 larger areas of this dead timber furnished fuel for devastating for- 

 est fires, with the result that in most cases there was a total loss. 



The Engelmann spnice beetle. — Another barkbeetle {Dendrocto- 

 nus engelmannl Ilopk.), similar in habits to piceaperda, has from 

 time to time during the past hfty years caused widespread devasta- 

 tions in the Kocky Mountains region to forests of Engelmann spruce, 

 in some sections killing from 75 to 00 per cent of the timber of mer- 

 chantable size. (Hopkins, 1908^, p. 1(>1 ; 19()9/a pp. 1-20-132.) 



The Bhivk IlUh beetle. — One of the most striking examples of the 

 destructive powers of an insect enemy of forest trees is found in the 

 Black Hills National Forest of South Dakota, where during the past 

 ten years a large percentage of the merchantable timber of the entire 

 forest has been killed by the Black Hills beetle {Dendroctomis pon- 

 derosir Hopk.). It is estimated that more than a billion feet of 

 timber have been destroyed in this forest as the direct result of the 

 Avork of this beetle. This destructive enemy of the western pine is 

 distributed throughout the forests of the middle and southern Rocky 

 Mountains region, where, within recent years, it has been found that 

 in areas of greater or less extent from 10 to 80 per cent of the trees 

 have been killed by it. (Hopkins. 1902«, 1903/;, 190r)7>, 1908r/, and 

 1909/>, pp. 90-101.) 



The mountain pine beetle and the western pine beetle. — The sugar 

 pine, silver pine, western yellow pine, and lodgepole \m\e of the 

 region north of Coloratlo and Utah, westward to the Cascades, and 

 southward through the Sierra Nevadas are attacked by the mountain 

 pine beetle {Dendrortronus monticohv Hopk.) and the western pine 

 beetle (Dendrorfonits brerirom/s I^ec), and, as a direct conse(|uence, 

 billions of feet of the timber have died. In one locality in north- 

 eastern Oregon it is estimated that 90 to 95 per cent of the timber in a 

 dense stand of lodgepole pine covering an area of 100.000 acres has 

 Ix'cii killed within the past three 3'ears by the mountain pine beetle. 

 Thioughout the sugar-pine districts of Oregon and California, as the 

 result of attacks by this same destructive barkbeetle, a considei-able 

 jjercentage of the largest and best trees is dead. ( AVebb. IDOC.; IIm|. 

 kins. 1908^, 1909/>, pp. SO-90.) 



T/te Douglas fr beetle. — The Douglas lir throughout the region 

 of the Rocky ^fountains from southern New Mexico to British Co- 

 lumbia has suffered severely from the ravages of the Douglas fir 

 beetle {Dendroctonus psendotsiK/d' Hojik.), with the result that a 

 large percentage of dead timber is found, much <if wjiich will be a 

 total loss. (Hopkins, 1909/;, pp. 10(>-114.) 



Three other species of beetles, having destructive habits similar 

 to those above mentioned, depredate on the pines of New. Mexico 

 12S77— Bull. ns. pt r>— 00 2 



