23 



marked during the fall months, after the main attack by the beetles is over. 



Plans should be made to handle the work most effectively. If sufficient 

 water is available, many of the logs may be floated as they are cut, or early in the 

 spring, and left for later sawing. 



If mills are available, portable or stationary, the remainder of the infested 

 logs should be sawn and the slabs burned before the first of June. The control 

 work may begin in November and should be completed by the first of June or 

 earlier. If mills are not available for the profitable use of the timber, or if it is 

 found impossible to saw all the infested logs within the time limit, a sufficient 

 number should be cut and barked, and, if necessary, the bark should be burned 

 within the proper time. 



Infested timber which cannot be used profitably for lumber should be cut 

 and barked or burned outright during winter, under proper supervision. 



The object should be to destroy the broods in as many of the infested trees 

 as possible. If over three-fourths of the infested trees of an isolated district can 

 be handled properly in one winter, the outbreak will be checked for several years, 

 and a little similar work the following winter should bring it under complete 

 control. If control work is undertaken in a section of an infested region, some 

 annual work will be required to hold in check reinfestation from neighboring 

 timber. Co-operation of the holders of adjoining timber lands will often be 

 necessary. 



Whenever the Red Turpentine Beetle is seriously involved, the infested 

 stumps should be barked before spring opens. 



MINOR INJURIES TO BULL PINE. 



In addition to the three species discussed, many bark-beetles breed in the bark 

 of the diseased and dying trees and logs. Certain of these enter the bark shortly 

 after the attack by the Western Pine Bark-beetle or the Mountain Pine Bark- 

 beetle, and are important secondary enemies; but they apparently attack 

 perfectly sound timber only rarely in British Columbia. They assist the primary 

 enemies in hastening the death of the trees, and cause further injury by killing 

 trees more or less weakened by storms, fires, or other causes. Certain species 

 breed only in the bark of rapidly dying trees and recently felled logs or stumps. 



Among these secondary enemies are numbers of species belonging to the 

 genus Ips (or Tomicus). Of these the most interesting are Ips integer Eichh., 

 I. emarginatus, I. interpunctus, I. oregonis, and several undescribed species. 

 These beetles are readily distinguished by their rather elongate cylindric form, 

 with the declivity, or hinder face of the elytra, steep, usually deeply excavated, 

 with the margin of the excavation more or less acute and armed with spines. 



They are true bark-beetles, rearing their broods in the inner bark; but 

 cutting tunnels quite different from those of Dendroctonus. One male and from 

 two to several females inhabit each set of egg-tunnels. The entrance-hole opens 

 into a flat "nuptial-chamber" situated between the inner bark and the wood 

 surface, usually engraving both. In this chamber the male is usually found 

 removing the boring-dust produced by the tunnelling of the females. Each 

 female excavates for herself an elongate egg-tunnel opening from the nuptial- 

 chamber, and deposits eggs singly in niches cut alternately at intervals along the 

 sides. The larvae bore through the inner bark away from the egg-tunnels, pupate 

 in the ends of the larval mines, and finally escape through round holes cut through 

 the bark. There are usually two broods each season. 



