- INSECT ENEMIES OF THE KEDWOOD. 



37 



An examination of Lawwoii'is C3'pres«, which had Ix'cn transphuitcd 

 in the park at Del Monte, showed that the Lawson's Cvpress bark- 

 beetle has the common habit of boring- into the liA'ing bark at the base 

 of perfectl}' health}" twigs (fig. 3, a). It was also found that tliis 

 injuiy would often result in the death of the lateral and defonuit}' of 

 the central twigs (fig. 3, Z-), while in man}" cases the wound would I)e 

 covered with gum (lig. 3, c) and heal without any serious harm. This 

 is conclusive evidence that the Ijeetle attacks healthy plant tissue of 

 the Lawson's Cypress. This was further verified bv specimens of 



Fig. 3. — Work of the Lawson's Cypress bark-beetle in twigs of living trees: a, burrows at base of twig; 

 b,b, wounrls covered with gum; c, deformed twig; d, wound where twig has died and fallen 

 (original). 



wood from a Lawson's Cypress said to have been killed by the beetle, 

 which were kindl}^ submitted to the writer b}" Professor Woodworth, 

 entomologist of the California experimental station at Berkeley. An 

 examination of this specimen showed in the healed-over wounds made 

 by the beetles that at least tw^o successive annual attacks on the living 

 bark had been made before the tree died. Nevertheless, the annual 

 rings of wood showed nearly a normal growth and indicated an other- 

 wise healthjr condition up to the jenv in which the tree died. It would 

 therefore appear that while the insect breeds normallv only in the 

 felled or otherwise injured trees, it is capable of attacking healthy 



