8 MISC. PUBLICATION 74, U. S. DEPT. OF AGBICULTUKE 



THE PINE AND HEMLOCK FLAT-HEAD BOKEKS 



Melanophila spp. 



Two species of the genus Melanophila, the eastern hemlock bark 

 borer (M. fulvoguttata Ham.) and the western flat-headed borer 

 (M. gentilis Lee), are of considerable economic importance. The 

 eastern form kills hemlock weakened by defoliation and other 

 causes. The western species is frequently an important pest during 

 epidemics of the western-pine bark beetle in western yellow pine and 

 to trees affected by drought (£, 4-6). 



THE TWIG TUNNELERS 



Oberea spp. 



Several species of Oberea bore down through the pith in the 

 twigs of several species of trees and shrubs, causing the death of 

 the infested portion. The work can always be distinguished from 

 that of other twig girdlers by the linear series of small holes cut 

 through the bark. 0. ray of s Hald. in rhododendron and azalea, 0. 

 schaumii Lee. in poplar, and O. tripunctata Fab. and 0. himaculata 

 Oliv. in plum, apple, peach, and dogwood are the most impor- 

 tant (IS). 



THE LONG-HORNED GIRDLERS 



Oncideres cingulata Say 

 Oncideres putator Thorn. 



The hickory twig girdler (Oncideres cingulata) and the huisache 

 girdler (0. putator) cause considerable damage to a great variety 

 of hardwood trees in the Eastern and Gulf States by cutting off the 

 branches. The girdling is done by the adult beetle (18, 37). 



THE COTTONWOOD BORER 



Plectrodera scalator Fab. 



In the central part of the United States the Cottonwood borer 

 causes serious injury to the base and roots of several species of 

 Cottonwood and willow. It is sometimes abundant enough in certain 

 localities to kill these trees (52). 



THE PRIONID ROOT BORERS 



Prionus spp. 



Several species of these large roundheaded borers — Prionus lati- 

 collis Drury and P. imhricomis L. in the East, and P. calif ornicus 

 Motschulsky in the Western States — bore in the roots of living 

 hardwoods, thus lowering the vitality of the trees. The attack is 

 frequently followed by root rots such as Armellaria and attacks of 

 secondary bark borers which ultimately kill the trees (16) . 



THE RED OAK BORER 



Romaleum rufulum Hald. 



The red oak borer is of considerable economic importance through- 

 out its range in the central and eastern part of the United States and 

 Canada. The habits of this species somewhat resemble those of 



