14 THE SCOLYTID BEETLES. 



In species 12 and 13 the egg galleries are long, longitudinal, straight, 

 or slightly winding, sometimes branched, and moderately broad ; the 

 larval mines are long, independent of each other from the start, 

 winding, and more or less regular. 



In species 14 to 21, so far as observed, the egg galleries are broad, 

 moderately long, straight, irregularly branched at terminals, and 

 usually with an inner gallery through the packed borings of the 

 finished egg galleries; the larval mines are long, connected toward 

 the egg gallery, independent and irregular, or forming a broad larval 

 chamber. 



In species 14, 15, and 17 the larval mines are connected toward 

 the egg gallery and separated toward the middle and outer ends. 



In species 19 and 20 the larvae excavate a common or social cham- 

 ber, sometimes with independent mines extending from the edges. 



In species 22 and 23 the egg galleries are broad to very broad, 

 short to very long, and straight or slightly winding, and the larval 

 mines form very large common chambers, with the pupal cells in the 

 chamber or at the ends of short independent mines extending from 

 the edge of the chamber. 



DISTRIBUTION. 



The distribution of the species of Division I is from the South 

 Atlantic States to Mexico and Central America, and northward into 

 the Rocky, Sierra Nevada, and Cascade mountains to British 

 Columbia. 



Species 1 occupies the region of the western yellow pine west of 

 western Montana and southern Idaho, southward to Santa Barbara 

 County, Cal., while species 2 occupies the Rocky Mountains region 

 south of central Colorado and central Utah, into southern California 

 and northern Mexico. 



Species 3, 5, and 8 occupy practically the same region as species 2, 

 while species 4 occupies the region of yellow pine, loblolly pine, and 

 longleaf pine south of Pennsylvania and westward into Texas, and 

 species 6 and 7 occupy the pine regions of the mountains of southern 

 Mexico. 



Species 9 occupies the region of silver pine, lodgepole pine, and 

 sugar pine north of Colorado and Utah and westward into the Sierra 

 Nevada and Cascade mountains. 



Species 10 occupies the region of the Rocky Mountain variety of 

 the western yellow pine and limber pine above an altitude of 6,000 

 feet, from western South Dakota southward through Wyoming, 

 Colorado, and Utah to southern New Mexico and Arizona, while 

 species 11 occupies the Jeffrey-pine region from the mountains of 

 San Bernardino County, Cal., to northern California, and probably 

 into Oregon. 



