S HA DE 1 B&B EE LLNS EC Ts 
be sprayed with penetrating contact insecticides to kill the larve 
when small. The larve are too small to dig out or kill with a wire. 
BARK BEETLES 
129. SCOLYTIDA. The beetles belonging to this family are 
commonly known as the bark beetles, bark borers, or ambrosia beetles. 
They are very small, cylindrical, black or brown, and seldom much 
over one-fifth inch in length. The adult female of the bark beetles 
burrows through the bark and makes a gallery in the cambium 
layer, in which she lays her eggs. The eggs hatch, and the legless 
grubs mine through the cambium layer in such a peculiar and char- 
acteristic manner that it is easier to tell many of the species by the 
burrow than by the adult beetles. The ambrosia beetles burrow 
more deeply into the wood and cultivate ambrosia, or a fungous 
growth, within the galleries, upon which they feed and upon which 
to feed the young. 
18 HICKORY BARK BORER 
Family SCOLYTID. Species Eccoptogaster quadrispinosus Say 
130. ‘The hickories in many sections have been killed by the 
hundreds by this pest. It works so secretly that frequently the 
trees are dying before the presence of the pest is suspected. The 
outbreaks that occur from time to time probably follow injury to 
the trees by adverse weather conditions or injury from leaf eating 
or other insects. This species has been considered in the literature 
mostly under the name Scolytus quadrispinosus Say. Riley de- 
scribed the female as Scolytus carye, but this name was dropped 
on finding that the difference was due to the difference in sex. It 
has recently been changed to the genus Eccoptogaster. 
131. Habits. ‘The dark brown or black beetles, about one- 
fifth inch long, emerge during the last of June and July through 
holes in the bark about the size of number eight shot. They feed 
for a time upon the young nuts, at the base of the leaves, or burrow 
into the young twigs, causing them to wilt, die or fall. The wilting 
or falling of these leaves and twigs is usually the first signs of their 
presence, and should be the warning to watch for more serious in- 
jury later. 
132. During August, the females begin to burrow into th 
bark, usually starting their galleries in a crack or under a bark 
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