Heavy two-inch or three-inch stuff is also liable to attack even in loose piles with lumber or cross sticks. An example of the latter was found in a valuable lot of mahogany lumber of first grade, the value of which was reduced two thirds by injury from a native ambrosia beetle. Numerous complaints have been received from different sections of the country of this class of injury to oak, poplar, gum, and other hardwoods. In all cases it is the moist condition and retarded drying of the lumber which induces attack; therefore, any method which will provide for the rapid drying of the wood before or after piling will tend to prevent losses. It is important that heavy lumber should, as far as possible, be cut in the winter months and piled so that it will be well dried out before the middle of March. Square timber, stave and heading bolts, with the bark on, often suffer from injuries by flat- or round-headed borers, hatching from eggs deposited in the bark of the logs before they are sawed and piled. One example of serious damage and loss was reported in which white pine staves for paint buckets and other small wooden vessels, which had been sawed from small logs, and the bark left on the edges, were attacked by a round-headed borer, the adults having deposited their eggs in the bark after the stock was sawn and piled. The character of the injury is shown in Fig. 29. Another example was reported from a manufacturer in the South, where the pieces of lumber which had strips of bark on one side were seriously damaged by the same kind of borer, the eggs having been deposited in the logs before sawing or in the bark after the lumber was piled. If the eggs are deposited in the logs, and the borers have entered the inner bark or the wood before sawing, they may continue their work regardless of methods of piling, but if such lumber is cut from new logs and placed in the pile while green, with the bark surface up, it will be much less liable to attack than if piled with the bark edges down. This liability of lumber with bark edges or sides to be attacked by insects suggests the importance of the removal of the bark, to prevent damage, or, if this is not practicable, the lumber with the bark on the sides should be piled in open, loose piles with the bark up, while that with the bark on the edges should be placed on the outer edges of the piles, exposed to the light and air. [Illustration: Fig. 29. Work of Round-headed Borers, _Callidium antennatum_, in White Pine Bucket Staves from New Hampshire. _a_, where egg was deposited in bark; _b_, larval mine; _c_, pupal cell; _d_, exit in bark; _e_, adult.]