16 



on hackberry), is represented in the West by several species which 

 infest conifers,. The genus is of especial interest on account of the 

 destructive powers of some of its representatives, which are capable 

 of attacking and living in the bark of healthy trees. One or more 

 unrecognized species allied to S. prceceps were found to be primarily 

 destructive to the wood of living white fir trees in all of the localities 

 visited. The beetles attack the bark of healthy, vigorous trees and 

 excavate their primary, or egg-galleries transversely through the inner 

 bark and through the outer surface of the wood. When the attack is 

 not sufficient to kill the trees, these wounds heal over, but in the mean- 

 time a decay often sets in at these injured places, which extends through 

 the heart wood and for several feet above and below the wound, thus 

 rendering the wood worthless for lumber, and often for fuel. That 

 these trees were in a vigorous, growing* condition when attacked was 

 proven b} T the fact that in many instances a normal growth of wood 

 and twigs had formed the year the attack was made, and when the 

 injury was not sufficient to weaken the vitality of the tree a normal 

 growth was made the next and succeeding years until the wounds were 

 healed. At Port Williams, Wash. , many trees were dying, all of which 

 were infested with larvae and pupa? of one or more of these Scolytus 

 enemies, and it was quite evident that they had been the primary cause 

 of the trouble. t . 



Another species, at present recognized as jS. tmispmosus, was found 

 to be a very common enemy of red fir along the coast, and of the red fir 

 and Western larch in Idaho and eastern Washington. No evidence was 

 found, however, that this species had caused the death of any of the 

 trees. 



The genus Tomieus. — This genus is represented in the collection by 

 some ten species, four of which appear to be new. While I found 

 some evidence to indicate that a species recognized as Tomieus pini 

 was the primary cause of the death of numerous examples of the lodge- 

 pole pine in the vicinity of Spokane and of yellow pine near Moscow, 

 Idaho, the other species appeared to occur only as secondary enemies 

 or as allies of the more aggressive Dendroctonus. 



Other Scolytids. — Among the other numerous species of Scolytids 

 collected, none were recognized as specially destructive enemies of 

 trees, except LeConte's Hylesinus aspericolMs, which is not a Hylesinus, 

 but appears to represent an undescribed genus, characterized by a 

 seven-jointed antenna! f unicle. This I found infesting the living bark of 

 white alder (Alniis rhombifolia), with evidence that it not only hastens 

 the death of injured trees, but that it may be the primary cause of the 

 death of healthy ones. 



Examples of larvae and pupae, with a few dead adults, of an unde- 

 scribed Hylesinus were found quite abundant in the bark of a felled 

 hemlock at Newport, Oreg. This and the one found in alder are of 



