THE GENUS DENDROCTONTJS. 
83 
HABITS. 
This species apparently prefers to attack injured and felled trees, 
but is often found attacking healthy living ones. It infests at least 
Fig. 46.— The mountain pine beetle: Egg galleries and larval mines grooved in surface of wood. 
(Author's illustration.) 
four species of pine and one species of spruce, and will doubtless be 
found in other species of pine and spruce growing within its range. 
The parent adults excavate their long, nearly straight, or winding, 
longitudinal galleries through the living inner bark, and groove the 
