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



Species of Pissodes Hosts and distribution 



burkei Hopk Alpine fir. Rocky Mountains. 



calif 'omicus Hopk Ponderosa pine. California. 



coloradensis Hopk Spruces and western white pine. Rocky 



Mountains. 



costatus Mann Sitka spruce. California to Alaska. 



carriei Hopk Western white pine. Northern Rocky Mountains 



and northward into Canada. 

 fasciatus Lee Douglas-fir. California, Oregon, Washington, 



Idaho, and British Columbia. 

 murrayanae Hopk Lodgepole pine. Eastern Oregon, Washington, 



and the northern Rocky Mountain region. 

 piperi Hopk True firs. California, Oregon, Washington, 



Idaho, and British Columbia. 

 radiatae Hopk Monterery pine, Bishop pine, knobcone pine, 



and lodgepole pine. Pacific coast. 



schwarzi Hopk Ponderosa pine. Rocky Mountain region. 



webbi Hopk Ponderosa pine, Mexican white pine, and 



lodgepole pine. Southwest. 

 yosemite Hopk. (fig. 82) ... . Ponderosa pine, Jeffrey pine, sugar pine, and 



western white pine. California, Oregon, and 



Washington. 

 (See also terminal-feeding Pissodes, p. 39.) 



PITCH MOTHS 



Several species of moths, belonging to different families, attack 

 the bole and larger limbs of living forest trees. Eggs are laid on 

 wounds or on the bark surface, and the caterpillars which hatch 

 therefrom mine into the inner bark and feed on the exudation of 

 pitch. These larval galleries are filled with a thick, gummy pitch, 

 and a large mass of pitch accumulates on the outside of the bark 

 at the point of attack. Because of the character of their work they 

 are called pitch moths. Some species are very injurious to the tops 

 of trees, but most simply extend local wounds and do not threaten 

 the life of the trees. 



One large group of these pitch moths, or clear-winged moths, 

 belonging to the family Aegeriidae, work in the inner bark and 

 bore into the wood of various forest trees. They are called clear- 

 winged moths because of the absence of scales on the wings and 

 the general resemblance to wasps. The caterpillars are naked or 

 have only a few prominent hairs. There are several important spe- 

 cies which attack coniferous trees. 



The sequoia pitch moth (Vespamima sequoia (Hy. Edw.)) (15, 

 158) attacks pines, Douglas-fir, and possibly other conifers in the 

 Pacific Coast and northern Rocky Mountain States. Although the 

 caterpillars of this moth are frequently found working in large 

 pitchy masses on wounds of forest trees, the species is not a 

 serious enemy. Sometimes breakage follows the attacks on small 

 trees, or the pitchy, healed-over galleries cause defects in the 

 lumber. 



The adults are clear-winged moths about % inch in length, 

 somewhat resembling a wasp or yellow jacket, as the body is 

 marked with yellow lines. The caterpillars are dirty-white or yel- 

 lowish and about 3 4 inch long when full grown. 



The adults appear in the latter part of June and in July and 



