While I was in camp one evening, in the midst of these tree studies, the veteran pine, now dead, was again struck by lightning. As everything was drenched with rain, there appeared to be no likelihood of fire. However, the following morning the old pine was ablaze. In extinguishing the fire I found that it had started at the base of the tree at a point where the bolt had descended and entered the earth. At this place there was an accumulation of bark-bits from the trunk, together with fallen twigs and needles from the dead tree-top. Thus a dead, inflammable tree in the woods is kindling which at any moment may become a torch and set fire to the surrounding green forest. Although fires frequently sweep through and destroy a green forest, they commonly have their start among dead trees or trash. The pine beetle just mentioned attacks and burrows into trees for the purpose of laying its eggs therein. When few in number they confine their attacks to trees of low vitality,--those that will easily succumb to their attack. The speedy death of the tree and the resultant chemical change in its sap appear to be necessary for the well-being of the deposited eggs or the youngsters that emerge from them. When these beetles are numerous they freely attack and easily kill the most vigorous of trees. The pine beetle is one of a dozen species of bark beetles that are grouped under a name that means "killer of trees." Each year they kill many acres of forest, and almost every year some one depredation extends over several thousand acres. The way of each species is similar to that of the others. The beetles of each species vary in length from a tenth to a fifth of an inch. They migrate in midsummer, at the time of the principal attack. Swarming over the tree, they at once bore into and through the bark. Here short transverse or vertical galleries are run, and in these the eggs are laid. In a short time the eggs hatch into grubs, and these at once start to feed upon the inner bark at right angles to the galleries, extending to right and left around the tree. It does not require many of them to girdle the tree. Commonly the tree is dead in two months or less. All these little animals remain in the tree until late spring or early summer, when they emerge in multiplied swarms and repeat the deadly work in other trees.