[Illustration: Adult of the red-shouldered shothole borer, a bostrichid beetle.]
_Cover:_ Adult of an anobiid beetle, _Xyletinus peltatus_, and pine sill damaged by larvae of this beetle.
The porosity of the wood, the moisture content, the starch or cellulose content--these also relate to egg laying.
The adults of some species remain on the wood from which they emerge, and reinfest it. Others crawl or fly to similar wood and attack it.
A beetle may lay only a few eggs or as many as 60 or 70; the number depends on the species of beetle and on the condition of the wood.
Seasoned hardwoods.--Beetles that infest seasoned hardwoods lay eggs on or in the wood from which they emerge. Hence the same wood may be infested repeatedly. These beetles do not require bark for egg laying.
[Illustration: Oak board damaged by larvae of the southern lyctus beetle.]
Lyctus beetles lay eggs in exposed pores in the sapwood of oak, ash, hickory, walnut, pecan, gum, persimmon, maple, cherry, and a few other hardwood species. The larvae are found in hardwood flooring, furniture, picture frames, and trim.
Anobiid and cerambycid beetles lay eggs in crevices on the surface of the wood; cerambycids also lay eggs in emergence holes.
Bostrichid beetles that bore into seasoned hardwoods often bore chambers at the sides of their tunnels and lay eggs in them.
Unseasoned hardwoods.--Bostrichids that infest green and seasoning hardwoods lay eggs in pores leading from the entrance tunnels. The red-shouldered shothole borer is one of these. Bostrichids frequently attack bark-covered wood. They usually do not reinfest the wood from which they emerge.
Seasoned softwoods.--Some kinds of beetles infest seasoned softwood lumber used in the structure of buildings.
Certain of the bostrichids require bark for egg laying. They infest lumber that has bark on the edges. Such lumber is often used in framing, subflooring, and roofing. The females lay eggs in the bark. The larvae of some species complete their development in it; others go to the adjacent wood to do so. The adult females may reinfest the wood from which they emerge.
Other beetles that infest seasoned softwoods do not require bark for egg laying. Among them are the old house borer and the cossonid weevils. The females lay eggs in crevices in the wood. They may infest the same wood repeatedly.