DAMAGE CAUSED BY ANIMALS. 143 



be pulled out by the roots and burned, whilst poles should be 

 felled and barked, and the bark burned. 



69. The crooked-toothed Silver Fir Bark-beetle, Bostrichus 

 (Tomicu*) curvidens. 



This beetle, which is O'lO to 0*128 inches in length, is deep- 

 brown to black in colour, with long brownish-yellow hairs, whilst 

 the female in particular is characterised by a close, golden yellow, 

 frontal tuft of hair. The elytra have very deep longitudinal 

 stripes with rows of fine punctures, and their edges at the 

 somewhat abrupt termination have 5 to 7 teeth on each side on 

 the male insect, of which 3 are much curved, whilst only 

 3 to 4 projections are noticeable on the female. 



B. curvidens is to be found almost exclusively on the Silver 

 Fir, and only exceptionally on any other conifer. It principally 

 attacks stems in tree-forest, beginning its attacks in the crown and 

 gradually working its way down the bole ; it has also, however, 

 been known to attack pole-forest at times, but has not yet 

 been proved to be destructive to younger crops. 



Swarming as early as the end of March and the beginning 

 of April, it undoubtedly has a two-fold generation within the year. 

 The main galleries are mostly two-armed and horizontal, although 

 there are many deviations from their normal characteristic form, 

 including galleries at many different angles, but never approach- 

 ing the vertical like B. typographus. Both the main and the 

 larval galleries eat a little way into the sapwood, whilst the 

 pupal chambers are often formed for the most part in it, 

 and are consequently filled up with bore-dust. 



Its attacks are chiefly confined to trees near the edges 

 of compartments, or to standards in the more or less full 

 enjoyment of light and warmth; but under favourable circum- 

 stances the insect can reproduce and multiply itself so quickly 

 as to cause very serious damage in Silver Fir woods, hence 

 sylviculturists have every reason to keep a careful look-out 

 for the commencement of any attacks. 



The same general protective and annihilative measures may be 

 adopted as in the case of the other bark-beetles ; but when 

 barking fallen trees, it must be borne in mind that on stems, 

 or portions of stems, which have thin bark, the chrysalides often 





