THE GENUS DEXDEOCTONUS. 



113 



rado Springs, Fort Garland, Glenwood Springs, Gunnison National 

 Forest, Green Mountain Falls, Hahns Peak, Husted, Indian Creek, 

 Larlcspur, La Yeta, Manitou, Medicine Bow National Forest, Meeker, 

 Monte Vista, Ouray National Forest, Palmer Lake, Pikes Peak, Pine, 

 •Ponclia Springs, San Isabel National Forest, San Juan National For- 

 est, Sequache, Uncompahgre National Forest, White River National 

 Forest. New Mexico: 

 Gila National Forest, 

 Vermejo. South Da- 

 liota: Custer, Elmore, 

 Hill City, Lead, Nemo, 

 Piedmont, SylvanLake. 

 Utah: Escalante, Ka- 

 mas, Kanab, La Salle 

 National Forest, Pan- 

 guitch, Provo. Wyo- 

 ming: Downingt on. En- 

 campment, Keystone. 

 Additional locality from 

 other collectors : (Brown) 

 Las Animas County, 

 Colo. Localities rejiort- 

 ed hy corres-pondents: 

 Eagle, Florissant, Idaho 

 Springs, Kennedy Sta- 

 tion, La Veta, Montrose, 

 Pagosa Springs, Porter, 

 San Juan,Ute Pass, and 

 West Cliff, Colo. 



Host trees. — Pinus 

 'ponderosa scopulorum, 

 P. Jlexilis, P. murraij- 

 ana, P. strohiformis , and 

 Picea engelmanni. 



Economic relation to 

 forests. — This species is 

 exceedingly destructive 

 to the pine forests of 

 the central and southern Rocky Mountain region, having caused a 

 loss of forest resources worth many millions of dollars. The rock 

 pine, or bull pine {Pinus ponderosa var. scopulorum), is its favorite 

 host tree, but it attacks and kills the other pines and infests the 

 spruce, though apparently not destructive to the latter. 



Identified specimens. — Le Conte (M. C. Z.), 1 specimen; Horn (A. E. 

 S.), 2 specimens; A. N. S., 2 specimens; U.S.N.M., 1 specimen; 

 79980—09 9 



Fig. 70. — Dcndroctonus ponderosx: Tree with bark removed, show- 

 ing egg galleries grooved and marked on surface of wood. (Orig- 

 inal.) 



