11 



ating galleries from a single entrance and a central chamber (fig. 2, a 

 and &). The central chamber may (a), or may not (#), extend through 

 the inner layers of bark and groove the surface of the wood, but the 

 radiating galleries are nearly always grooved in the surface of the 

 wood, us are also the egg cavities, which are excavated at short inter 

 vals along the sides (tigs. 3 and 4). These grooved and notched carv- 

 ings are often very conspicuous in the surface of the wood of trees 

 and logs for many years after the bark is removed or has fallen away. 

 The number of galleries branching from the central chamber varies 

 from two to five or 

 six, but the normal 

 number is four two 

 above and two below 

 the entrance. The 

 mode of development 

 of the young stages is 

 the same as in the pre- 

 ceding species. (See 

 PL V.) 



This is a common 

 enemy of the rock pine 

 ( / V/f us pon derosa sco- 

 pulorum) throughout 

 the Rocky Mountain 

 region and of P. pon- 

 der os a west of the 

 mountains. It is ever 

 ready to attack and 

 prevent the recovery 

 of trees of all sizes 

 which are suffering 

 from weakened vital- 

 ity. It is also at- 

 tracted to recently 

 felled trees, and breeds 

 in enormous numbers 

 in the bark on the tops and branches. The species was found to be 

 exceedingly common in trees infested by the pine destroyer and on the 

 logs and tops of those felled by the lumbermen. 



The coarse-writing bark-beetle (Tomicus calligraplius Germ. var. occi- 

 dentalis). This is much larger than the Oregon Tomicus, but is of the 

 same color and general form. Individuals vary in length from 4.5 mm. 

 to 6.5 mm. This species also follows closely the first attack by the 

 pine destroyer. It enters the bark from near the base to toward the 



FIG. 3. Work of the Oregon Tomicus. Primary galleries engraved 

 in surface of wood. Central chamber not extending into wood 

 except at a. Reduced about one-half (original). 





