INSECT ENEMIES OF WESTERN FORESTS 



35 



Other species of Pissodes which work in the terminals of young 



trees inckide the following: : 



Species 



Pissodes yosemitc Hopk PonderosM 



.sugar pine 

 iiigton. 

 Pissodes schwarzi Hopk Pouderosa pine 



Hosts and distribution 

 pine, western white 



pine, and 

 California, Oregon, and Wash- 



Roeky Mountain region. 



Certain species of the genus Magdalis are also twig borers during 

 the larval period (fig. 15). The adults feed on the foliage and make 

 ^Junctures in the twigs of conifers and broadleaved trees, in which 

 eggs are deposited. The grubs burrow beneath the bark and cause 



the death of small branches 

 and terminal twigs. The 

 larvae are Avhite, legless, 

 and curled and are practi- 

 cally indistinguishable from 

 those of Pissodes^ but the 

 work is usually distinct in 

 that the larval borings are 

 fine-grained and powdery 

 instead of shredded, and the 

 pupal cells are oval and 

 smooth, without the lining 

 of shredded wood fiber. The 

 adults are bright blue, 

 green, or black, with promi- 

 nent curved beaks. West- 

 ern species include the fol- 

 lowing : 



Hosts and distribution 

 Pines. Pacific States. 

 Ponderosa pine. Western States. 

 Lodgepole and other pines. Maine to British 



Columbia, New Mexico, and California. 

 Jeffrey pine. California. 

 Monterey and probably other pines. Cali- 

 fornia and Oregon. 

 Spruce. Colorado and other Western States. 

 Fruit trees and broadleaved trees. Califor- 

 nia, Nevada, and New Mexico. 

 Alder and apple. Alaska to California and 

 eastward to Montana. 



Figure 15. — Pine twig weevils {Magdalis lecontei), 

 natural size. 



Species 

 Magdalis lecontei Horn (fig. 15). 



Magdalis cuneiformis Horn 



Magdalis hispoides Lee 



Magdalis gentilis Lec-- 

 Magdalis proxima Fall. 



Magdalis alutacea Lec- 

 Magdalis gracilis Lec_ 



Magdalis aenescens Lec. 



TWIG BORERS AND GIRDLERS 



A few bark and wood boring insects {J/.0) belonging to the families 

 Buprestidae and Cerambycidae are of some importance as twig 

 borers, or girdlers, in various forest, park, and shade trees. 



Beetles of the family Buprestidae lay their eggs on the bark of 

 twigs, and the larvae, which are referred to as "flatheaded borers" 

 on account of their horseshoe-nail appearance, work under the bark 

 and into the wood, forming nearly flat tunnels filled with boring 

 dust. The larvae are slender and white, without legs, and the 

 enlarged forward segment of the body has horny plates on both the 



