the bark (fig. 90C). The gallery first runs horizontally or slightly 
upward; then it turns downward. When the attack is made just 
above the ground line the gallery may be continued below ground 
line along a large root. Eggs are laid in elongate masses along 
the sides of the gallery (fig. 90B). The larvae feed gregariously 
away from the gallery in the phloem. A fully-developed gallery 
may be be from a few inches to more than a foot wide. Pupation 
occurs in cells located between the bark and wood, either in the 
gallery or a short distance forward in fresh phloem. Adults 
emerge through holes chewed through the bark; sometimes sev- 
eral use the same hole. In southern latitudes and at lower eleva- 
tions, there may be two or three generations per year. Farther 
north and at higher elevations, there may be only one generation 
per year or every two years. 
In areas where lumbering is continued for several years, the 
red turpentine beetle often becomes very abundant. The sudden 
discontinuance of these operations, therefore, may lead to attacks 
on healthy trees causing catfaces and the killing of decadent trees 
in the stand. Shade tree pines in areas of new construction are 
also attacked and may be weakened or killed. Damage can be 
reduced or prevented by not chopping into trees, digging up or 
damaging roots, pushing deep earth fills over roots, or piling lum- 
ber or green logs near trees. It is also helpful to debark or spray 
freshly cut stumps and to cut and remove pines dying from other 
causes. Watering or fertilizing of individual trees also increases. 
their resistance. 
The eastern spruce beetle, Dendroctonus obesus (Mann). (= 
piceaperda Hopk.), occurs throughout the spruce forests of east- 
ern America, and breeds in native, red, white, and black spruces. 
The adult is dark brown to uniformly black and from 4.5 to 6.2 
mm. long. Normally windfalls, prostrate dying green trees, and 
overmature or weakened standing trees over 8 inches d.b.h. are 
attacked. During epidemics, however, almost all trees are at- 
tacked regardless of size or vigor. Attacks usually begin on the 
lower third of the bole except for the first two or three feet 
above the ground. Later in the season, they are continued upward | 
and downward, exclusive of limbs and parts of the trunk less 
than 8 inches in diameter. 
Females construct vertical, almost straight egg galleries in the 
phloem, engraving the wood. Eggs are deposited in groups along 
the side of the gallery. After the eggs are laid, the adults may 
vacate their galleries and construct new ones in the same tree 
or in nearby ones. They lay more eggs then die. The younger lar- 
vae feed gregariously; older ones singly, in individual mines. 
Pupation occurs in cells at the end of larval tunnels and the 
winter is spent in the bark in either the larval or adult stages. 
Signs of attack are red boring dust and pitch tubes on the bark, 
the fading and dropping of needles, and the reddish appearance 
of the twigs after the needles drop. 
Several outbreaks have occurred in eastern forests during past 
years. One, from 1897 to 1901, killed more than a billion board 
feet of valuable spruce in Northern New England and eastern 
Canada (368). The underlying causes of outbreaks are not well 
understood, but piles of slash in mature stands are believed to 
247 
