INSECT ENEMIES OF WESTERN FORESTS 



153 



The obtuse saw3^er {Monochamus ohtusus Csy.) is a small brown 

 beetle with gray markings, measuring from one-half to three-fourths 

 of an inch in length. The antennae are over twice as long as the 

 body, and the prothorax has a toothlike projection on each side. 

 The larvae are from 1 to II/2 inches in length and are destructive to 

 pine and Douglas fir in Idaho, Montana, California, and probably 

 other Western States. 



The black-horned pine borer {Gallidimn antennatum Newm.) (fig. 

 76) is a common species in western forests which attacks the logs 

 and limbs of dead ponderosa ]>iiie and sugar ])iiu\ It has recently 



Figure 76. — The black-horned pine borer (Callidium antennatum) : 

 C, adult ; D, larva making tunnels on edging of pine board. A, 



Larvae ; B, pupa 

 C, natural size. 



attracted attention as a destructive borer in lumber stored in mill, 

 yards in northeastern California, where it attacks strips of bark left 

 on the edges of lumber stock. The larvae work under this bark and 

 score the surface of the wood, then extend their mines into the sap- 

 wood for a depth of 2 or 3 inches. They also injure seasoned rustic 

 w^ork by mining out the cambium layer and causing the bark to 

 loosen from the log. The larvae are yellowish-white, apparently 

 legless grubs about three-fourths inch in length when full grown. 

 The adults are flat, shining, bluish-black beetles about one-half inch 

 in length, with antennae about half the length of the body. Other 

 closely related species are found in the various firs, pines, cedars, 

 and redwood. 



Other species of wood-boring ceramb3^cids w^hich may be en- 

 countered damaging the wood of western forest trees are the follow- 

 ing: 



Species Hosts and distribution 



Tragosoma harrisi Lee Pines. Western States. 



Asemuni atrum Esch Pines, firs, and spruce. Western States. 



Asemuni nitidum Lee Pines, firs, and Douglas fir. Pacific coast. 



Criocephalus productus Lee Pines, firs, and Donglas fir. Western States. 



Criocephalus dsperatus Lee Pines. Oregon and California. 



