THE PINE INVESTIGATION. 295 



discovered by which the then healhty and more valuable port- 

 ions of these forests could in a measure, be protected. 



The methods of cutting and burning the infested trees, or 

 removing the bark, as is practiced in European forests against 

 like troubles, was, owing to the existing conditions in our for- 

 ests, impossible, or at least impractable. 



THE IMPORTATION OF NATURAL ENEMIES OF BARK BEETLES CON- 

 SIDERED. 



Upon my finding, early in 1891, that the European fruit bark 

 beetle, Scolytus rugulosus, was quite common and destructive 

 to fruit trees in various sections of the State, which, in addition 

 to the devastations previously observed in the spruce forests, 

 which was believed to be the work of bark beetles, I realized 

 that we had among the introduced and native bark beetles, 

 some of the most destructive forest and fruit tree pests known, 

 and that in the study of their habits, life histories, natural 

 enemies, an T d methods of combatting them, was a great prob- 

 lem demanding special attention. In the consideration of 

 remedies at that time, it occurred to me that if some parasitic 

 and predaceous enemies of bark beetles could be imported from 

 Europe, that possibly they would render valuable service in 

 keeping our destructive species within proper bounds, since it 

 was then thought (Bulletin 17, p. 99,) as subsequent obser- 

 vations demonstrated, that the bark beetles can kill trees only 

 when occuring in excessivive numbers, and that if for any cause 

 the excess is reduced, their destructive powers are ended, so 

 far as attacking and killing trees is concerned, and that any- 

 thing which will prevent their excessive multiplication, will, at 

 the same time, prevent further death of trees from their attack. 

 In the following July, when I found that the pine timber was 

 dying evidently from the attack of bark beetles, I gave the 

 subject of importation of parasites especial attention, as the 

 following correspondence and accounts of subsequent events 

 will show. Through the kindness of the Government Entomol - 

 ogist, Dr. C. V. Kiley, I was, in June, 1891, placed in corres- 

 pondence with one of the Emperor's chief Oberforesters, W. 



