THE PINE INVESTIGATION. 391 



worthy of recommending, is that of a Frenchman, M. Robert. 1 

 who found that by removing the coarse outer bark, and cutting: 

 narrow strips of bark from the .trunk of infested elms, the 

 Scolytids were either killed or driven out by the increased vig- 

 or of the tree and the greater quantity of sap which it is well 

 known will result from this treatment. The same result I have 

 myself found may be accomplished by simply scoring, with a 

 penknife, the trunk and larger branches of fruit trees suffering 

 from what is termed "bark bound." In such cases, the cut 

 edges of the bark will rapidly separate, and a vigorous growth 

 of the tree will follow. This method can not be practiced how- 

 ever, except on fruit and shade trees, 



80 far as an invasion by the destructive species which prefer 

 to attack the healthy trees of a forest is concerned, there is no 

 remedy except the possible introduction or encouragement of 

 such enemies as will reduce their numbers or prevent an ex- 

 cessive increase. In fact this is all that is necessary to check 

 the ravages of this class of insects, on healthy trees since they 

 can only overcome the resistance exerted by the living wood 

 and bark when the attack is made in great numbers. 



A KNOWLEDGE OF THE INSECTS AND THEIR HABITS MAY PREVENT 

 SERIOUS LOSSES FROM THEIR RAVAGES. 



A knowledge of the habits of this class of insects, the char- 

 acter of their work, and the conditions favorable and unfavor- 

 able for their attack and increase may prevent serious loss of 

 timber, since by this knowledge trie owner of the attacked or 

 threatened timber may make preparations as soon as the in- 

 vasion commences, to work up, and as far as possible utilize 

 the timber as last as it dies, or even before it is attacked. In- 

 formation as to the ending of a trouble caused by them may al- 

 so be of especial service to the owners of valuable tracts of 

 timber, since it would prevent them from disposing of it at a 

 sacrifice. 



Thus, in many respects, it is of especial importance that 

 owners of forest, shade, and fruit trees should learn as 

 much as possible about the habits and character of this class of 



\. 5th Bep't U. S. Ent. Com. p 39 ; quoted from Miss Qrmerod, 



