148 MISC. PUBLICATION 273, U.S. DEPT. OF AGRICULTURE 



are the same. Some rather extensive operations have been carried 

 on in Arizona to control this beetle. 



The Vancouver ips (Ips vancouveri Sw.) is also closely allied in 

 character and habits to I. confusus, but is slightly larger. The 

 adult beetles are reddish brown to black, about y 4 inch long, and 

 with five spinelike teeth on the margins at each side of the con- 

 cave elytral declivity, which is densely clothed with long, slender 

 hairs. These beetles usually attack decadent or weakened western 

 white pine, lodgepole pine, and Sitka spruce throughout the North- 

 west, but under favorable conditions will attack apparently healthy 

 trees. The gallery pattern is of a radiating, longitudinal type with 

 three to five short egg galleries extending up and down the tree 

 from the nuptial chamber. There are apparently two but possibly 

 three generations a year. 



The Cloudcroft ips (Ips cloudcrofti Sw.) is a secondary enemy of 

 pines in the high mountains of New Mexico. It is a slender species 

 with five pairs of spines on the elytral declivity and is closely re- 

 lated to I. confusus in character and habits. 



The emarginate ips (7. eniarginatus Lee.) is most frequently 

 found associated with the mountain pine beetle in its attacks on 

 ponderosa, lodgepole, and western white pines, and with the Jef- 

 frey pine beetle in Jeffrey pine, but occasionally kills trees by it- 

 self. This is the largest western species of Ips. Its range extends 

 through California, north to southern British Columbia, and east 

 through Idaho to western Montana. The adults are dark-brown, 

 cylindrical bark beetles about y 4 inch long, with three prominent 

 spines along each side of the elytral declivity, and a fourth nearly 

 obsolete spine. Their work is characterized by the long, straight, 

 nearly parallel egg galleries from 2 to 4 feet long, which run up 

 and down the tree and connect at different points (fig. 67). Owing 

 to the similarity in length and width of the egg galleries, its work 

 is often confused with that of the mountain pine beetle, with 

 which it is so often associated. However, the presence of a nuptial 

 chamber and the absence of packed boring dust in the Ips galleries 

 will distinguish their work. In the northern part of its range this 

 species has two complete generations a year, but in the southern 

 part there are a number of summer generations with considerable 

 overlapping of broods. Control work has included this species when 

 in association with more aggressive bark beetles, but no separate 

 control has ever been required. 



Knaus' ips (Ips knausi Sw.) attacks lodgepole, ponderosa, and 

 Arizona pines through the pine belt of Arizona, New Mexico, and 

 Colorado. It is usually a secondary enemy. In its habits, character 

 of work, and appearance it closely resembles its near relative, 

 I. emarginatus, and may be considered the southern Rocky Moun- 

 tain form of this beetle. 



The smaller western pine engraver (Ips latidens (Lee.)) usu- 

 ally confines its attacks to the tops and limbs of dying or weak- 

 ened pines. Under favorable conditions it has demonstrated its 

 ability to kill trees, particularly those weakened by mistletoe or 

 drought, and in some instances even healthy trees of small diame- 

 ter. It is a primary killer of digger pine and is common in the 



