INSECT ENEMIES OF THE EEDWOOD. 



37 



Au examination of Lawson's Cypress, which had been transplanted 

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

 beetle has the common habit of boring into the living bark at the base 

 of perfectly healthy twigs (lig. 3. (/). It was also found that this 

 injury would often result in the death of the lateral and deformity of 

 the central twigs (fig. 3. J), while in many cases the wound would be 

 covered with gum (fig. 3, r) and heal without any serious harm. This 

 is conclusive evidence that the beetle attacks healthy plant tissue of 



the Lawson's Cypre? 



This was further verified by 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, wounds covered with gum: c. deformed twig: d, wound where t\vig has died and fallen 

 (original). 



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

 which were kindly submitted to the writer by 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 two 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 healthy condition up to the year in which the tree died. It would 

 therefore appear that while the insect breeds normally only in the 

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



