THE GENUS DENDROCTONUS. 15 



The species of Division II range from Guatemala northward to 

 Alaska, eastward to the Atlantic coast, and across northern Europe 

 and Russia into Siberia. 



Species 12 occupies the regions and sections of eastern larch from 

 northwestern West Virginia, northward and westward, while species 

 13 occupies the region of the Douglas fir, bigcone fir, and western 

 larch from southern New Mexico and Arizona to Ventura County, 

 Cal., and northward into British Columbia. 



Species 14 occupies the region of red spruce from the high moun- 

 tains of Pennsylvania northward and from New Brunswick to north- 

 western Michigan, and probably northwestward to the 100th meridian. 



Species 15 occupies the region of Engelmann spruce from the white 

 spruce in western South Dakota westward, and north of southern 

 New Mexico. 



Species 16 occupies the white-spruce region in Alaska, and species 

 17 the Sitka-spruce region from southern Oregon to Sitka. 



Species 18 occupies the Lake Superior region; species 19 the region 

 of lodgepole pine from central Colorado northward probably into 

 British Columbia ; species 20 the regions of red spruce from the moun- 

 tains of West Virginia into New York; while species 21 occupies the 

 spruce and pine regions north of central Europe in Denmark and 

 through Russia to eastern Siberia. 



Species 22 occupies the region of pitch pine, Virginia pine, yellow 

 pine, loblolly pine, and longleaf pine from Long Island, New York, 

 east of the Allegheny Mountains, southward to Florida and Texas, 

 and west of the mountains from the Little Kanawha River probably 

 through Kentucky and Tennessee, while species 23 occupies the 

 regions of pine timber from the Atlantic to the Pacific north of the 

 South Atlantic and Gulf States and south into the mountains of 

 Guatemala. Species 24 is described from Guatemala. 



The distribution maps (figs. 11, 14, 17, etc.) show the known and 

 probable ranges of each species, the known range being indicated 

 by large dots and the probable range by small dots. 



The distribution of the genus is shown on a map of the world 

 (PI. II.) 



HOST TREES. 



In Division I the species confine their attack to pine and spruce, 

 but principally to the pines. 



Species 1 confines its attack to the western yellow and sugar pine, 

 and is a destructive enemy of both. Species 2 attacks the western 

 yellow pine, but, so far as observed, is much less destructive than its 

 northern and western neighbor. It has also been found in the Doug- 

 las fir, but this is evidently an abnormal habit. 



