THE GENUS DENDROCTONUS. 
157 
las fir, and it is not likely that it will infest these trees, but it has been 
found in the eastern larch. 
It is often exceedingly abundant in the stumps of felled trees 
where timber-cutting operations are carried on, in fire-scorched trees, 
and especially in the bark at the base of those killed by other species 
of Dendroctonus, or by lightning, or storm, or otherwise injured and 
broken. It shows a decided preference for the bark on the base of 
Fig. 99.— The red turpentine beetle. Work in bark at base of tree: a, Entrance and pitch tube; b, egg 
gallery; c, borirlg dust and resin; d, pupal cell; e, pupa; /, larvse 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. (Author's illustration.) 
pine trees and stumps, and is rarely common in the logs or prostrate 
trunks, even of pine. 
The parent beetles excavate their broad, irregular, sometimes 
branched, longitudinal egg galleries, from a few inches to many feet in 
length, through the inner living bark. If the bark is living and 
healthy and full of resin, the progress in making an entrance through 
the inner bark and extending the galleries is slow, and often large 
masses of resin or so-called pitch are pushed out at the entrance before 
