THE GENUS DENDROCTONUS. 



153 



labrum short, sides nearly parallel, and apex tuberculate. Protho- 

 raric tergum with two broad, shining dorsal plates separated by a 

 rather broad median space, and a smaller lateral plate each side; 

 stfrnellar lobes each with a faint foot callus; the mesoterga and 

 nu'taterga with shining plates on the lateral lobes. Abdomen with a 

 rather prominent.tubercle on each epipleurum. Larval type labeled 

 "Hopk. U. S. 2824." 



FIG. \+2.Dcndroctonw valens: Work in bark at base of stump, a, Entrance and pitch tube; b, egg gallery; 

 c, boring dust and resin; d, pupal cell; e, pupa; /, larvae at work feeding on inner living bark; g, exit 

 burrows; h, resulting old scar or basal wound, often referred to as basal fire wound; i, inner bark with 

 outer corky bark removed. ( Original. ) 



The larva of this species is scarcely to be distinguished from the 

 preceding. 



Galleries (figs. 91-93). The egg galleries are generally longitudinal, 

 more or less winding, and vary greatly in length, sometimes being 

 very long; they are irregular in width and sometimes with branches, 

 and are slightly grooved into the surface of the wood. The eggs 

 are placed in masses at intervals along the sides in the inner bark, 

 and the larvae excavate broad chambers, which vary in size from a 



