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



dying trees, but sometimes appears to be responsible for the kill- 

 ing of apparently healthy trees. The adults are black, about 1 inch 

 long, and have violet or bright-blue wing covers. S. ligneiis (F.) 

 is a black species y 2 inch long, with orange or red marking on the 

 wing covers. The variety ampins Csy. works under the bark of 

 juniper, cedar, cypress, and giant sequoia in the West. The variety 

 sequoiae Van. D. works in redwood in California. S. juniperi 

 (Fisher) feeds under the bark and in the sap wood of juniper in 

 the Southwest. S. litigiosa (Csy.) is similar, but confines its at- 

 tacks to white fir, red fir, and Douglas-fir in the Rocky Mountain 

 and Pacific Coast States. 



Other species of bark-boring roundheaded beetles are as follows : 



Species Hosts and distribution 



Atima dorsalis Lee California incense cedar and western red cedar. 



Pacific Coast States. 



hoppingi Linsley Alaska yellow cedar. Oregon and Washington. 



huachucae Champl. & Knull Arizona cypress. Arizona and New Mexico. 



maritima Linsley Monterey cypress. Coastal California. 



Leptostylus nebulosus Horn. True firs. Oregon and California. 

 Phymatodes decussatits 



(Lee.) White oaks. Pacific coast. 



dimidiatus (Kby.) Douglas-fir, fir, larch, and hemlock. Pacific 



Coast and Rocky Mountain States. 



lecontei Linsley Oak. Pacific coast. 



nitidus Lee Cypress, redwood, and California incense cedar. 



Pacific coast. 

 Semunotus juniperi (Fisher) Juniper. Southern California and the South- 

 west. 



BARK WEEVILS 



Some bark weevils of the genus Pissodes (7-4) are particularly 

 important as enemies of terminal shoots (p. 39) ; others attack the 

 basal portion of the trunk of small trees and may extend their 

 work into the roots. Weakened, suppressed, and decadent trees 

 are usually preferred, but under some conditions these insects may 

 attack healthy trees. Usually they breed under the bark of logs, 

 in stumps, or under the bark of dying, standing trees and hence 

 are of little economic importance (fig. 82) . 



The adults are stout beetles with uniform or variegated mark- 

 ings of yellow, brown, or black. The head is prolonged into a snout 

 or beak, which is used to puncture buds and tender bark of ter- 

 minal or lateral branches for feeding purposes, and in the female 

 to make a hole for the reception of the eggs. The larvae are small, 

 white, legless grubs, with curved cylindrical bodies. The larvae 

 mine under the bark and form winding galleries, gradually in- 

 creasing in size, which extend through the inner bark and some- 

 times score the sapwood. Each mine ends in a pupal cell con- 

 structed partly in the bark but mostly in the sapwood. This cell 



