THE GENUS DENDKOCTONUS. 5 



If, when first discovered, the depredations of the beetles have 

 already involved an extensive area, or if they are neglected until a 

 large percentage of the timber is killed, their artificial control will 

 be as difficult and expensive as that of a neglected forest fire. Further- 

 more, if the depredations occur m an inaccessible section of the 

 forest or where the conditions as to labor and other facilities are 

 unfavorable for necessary action, nothing more can be done toward 

 the control of the beetles than under the same conditions in con- 

 trolling a fire. But with the rapid extension of modern forest 

 management, lumbering operations, and working plans into the 

 principal public and private forests, and especially with the adoption 

 of fire-control regulations under an organization of fire patrols and 

 rangers, there will be no excuse for neglecting the insects. 



THE BEETLE PROBLEM AS IMPORTANT AS THE FIRE PROBLEM. 



In certain sections of the country and in certain National Forests 

 where the more destructive species of beetles are present and a 

 constant menace to the standing timber, the beetle problem is 

 undoubtedly as important as the forest-fire problem, and therefore 

 demands the adoption and organization of beetle-control work, which, 

 with little or no additional force and equipment, can be conducted by 

 fire patrols and forest rangers. 



The evidence of destructive beetle work is not quite as distinct 

 as is the evidence of fire, and can not be seen quite so far, but a 

 clump of yellow-top or red-top trees can be seen for a long distance, 

 and upon closer inspection the pitch tubes and boring dust on and 

 around the trunks of living trees are sufficient danger signals to 

 demand that the required action be taken to prevent widespread 

 depredations. 



There is one great advantage in the requirements for successful 

 beetle control over those for fire control, viz, there is usually a period 

 of six to ten months in which to utilize or otherwise dispose of the 

 affected timber to destroy the broods of beetles in the bark, while 

 a fire requires immediate attention. 



DISTINCTIVE CHARACTERS OF THE GENUS. a 



The beetles of the genus Dendroctonus (see figs. 1, 2, 3, etc.) are 

 distinguished in the adult stage by their cylindrical, somewhat 

 elongate to stout bodies, broad and prominent heads, nearly round 

 to oblong-oval and transversely placed eyes behind the base of 

 each antenna, the last with an elongate, clublike basal joint (scape) 

 followed by 5 short joints (funicle) and terminated by a broad club 

 which is thickened at the base and flattened toward the apex, and 



a See also Technical Series No. 17, Part I, for technical descriptions of genus, species, 

 etc. 



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