19 



than man}' an acre of timber in the Eastern States, one can have some 

 conception of the vast amount of timber which had been destroyed. 



While the caterpillars which were primarily to blame for this destruc- 

 tion have not attracted attention within recent years, they will doubtless 

 make their appearance again in destructive numbers and attack the 

 remaining timber, which is becoming each year more accessible to 

 lumbering operations, and hence rapidly increasing in value. 



BENEFICIAL INSECTS AND DISEASES. 



A large series of predaceous and parasitic insect enemies of the 

 principal destructive species was collected, and many features regard- 

 ing their occurrence, distribution, and habits noted. The predaceous 

 enemies of Scolytids were quite common in nearly all of the localities 

 visited, but the Chalcidid, Braconid, and Ichneumonid parasites of 

 Scolytids and other bark and wood-infesting insects were rare as com- 

 pared with the same class of insects in the East. 



Numerous examples of diseases of both injurious and beneficial 

 insects were found, and many insects had died from their effects. It 

 was not possible, however, with the limited time at my disposal to 

 determine the exact relation of these factors to the injuries caused by 

 the principal enemies. 



GENERAL OBSERVATIONS ON FOREST TREES AND FOREST CONDITIONS. 



Forest trees recognized and studied. — Some 22 species of conifers and 

 11 of deciduous trees were recognized on this trip and their insect 

 enemies studied, the following of which deserve special mention on 

 account of their common occurrence and commercial importance. 



COMMON NAMES. BOTANICAL NAMES. 



Redwood Sequoia sempervirens. 



Western yellow pine Pinus ponderosa. 



Sugar pine Pinus lambertiana. 



Silver pine (Western white pine) Pinus monticola. 



Red fir (Douglas spruce) Pseudotsuga taxifolia. 



Tideland spruce. Picea sitchensis. 



Red cedar Thuja plicata. 



Western hemlock Tsuga heterophjlla. 



Lowland fir Abies grandis. 



Noble fir (" larch ") Abies nobilis. 



Western larch Larix occidentalis. 



Each of the timber trees named in this list was found to have one or 

 more insect enemies. My observations on these trees and the relation 

 of their enemies to the general condition of the timber may be briefly 

 summarized as follows: 



The redwood. — This appears to be an exceedingly hardy tree, and so 

 far as I observed in the short time spent in the forests of this species in 

 the vicinity of Guerneville, Cal., is in a healthy condition. It has, 



