150 THE SCOLYTID BEETLES. 
in the bark of a living tree, they are often found filled with liquid 
resin, yet the larva? will continue their work, apparently undisturbed 
by it. The larvae, which are stout, cylindrical, yellowish- white, foot- 
less grubs, with broad dorsal plates on the last abdominal segments 
armed with 6 stout spines, transform to pupae and adults in separate 
or adjoining cells in the borings in the larval chamber, or in separate 
cells extended from the margin or into the roof of the chamber. 
TThen the broods cf adults are fully developed and ready to emerge 
they usually bore through the intervening bark and congregate in the 
main chamber, where they mate and await the proper time for them 
to emerge. They then bore a few exit holes, or utilize the ventilatine 
holes in the old gallery, through each cf which many individuals 
emerge. In localities where this species is abundant it sometimes 
congregates in swarms of greater or less extent, accompanied by 
associates, guests, and enemies (see pp. 159-160). 
ECONOMIC FE-OTTTiES. 
In general, this species is of secondary importance in its relation to 
the death of pine timber, but occasionally it has been found in 
role of the primary and only cause of the death of trees, especially on 
Long Island. Xew York, and in Xew Jersey. The principal injury, 
however, is usually confined to the base of living pine trees. The 
broad larval chambers separating the bark over areas of greater cr 
less extent might in many cases heal without serious harm, but the 
dead bark, with the pitch masses on the outside and the dried resin 
and borings beneath, offers the most favorable conditions for subse- 
quent injuries by forest foes, and thus these larval chambers are the 
primary cause of a very large percentage cf the so-called "foe scars" 
cr foe wounds which are so prevalent at the base and lower portic n 
c f the trunks of living t:ves in the South. If a forest tire burns the 
bark and resin and exposes the wood, it becomes dry and is usually 
mined by round-headed and flatheaded wood-borers. Or the v. 
may become either pitchy or decayed, so that the next lire burns 
d:eply into it and kills a larger area of the bark. Thus each subse- 
quent fire contributes to an extension of the wound until hi many 
eases the tree is so weakened that it is broken down by wind or 
attacked and killed by other barkbeetles. In the aggregate, 
primary injury by the beetle results in very extensive losses of some 
of th umber. 
EVIDENCES F ATTACK. 
The first evidences of the work of the beetle are found in fresh 
masses of pitch, or large pitch tubes, mixed with reddish borings, at 
or near the base i i living trees and the stum] - - ently felled ones. 
Subsequent evidence, until destroyed by fire, is found in the old pitch 
