The cerambycids, also known as roundheaded or long-horned beetles, are blue, black, or pale yellow to reddish brown, and often bear distinctive markings on the head or the wing covers. They are 1/2 to 1 inch long, and vary in shape. The old house borer belongs in this group. It is black, and has grayish markings on the wing covers. It is about 3/4 inch long. Cossonid weevils are reddish brown or black, 1/8 to 1/5 inch long, and oval to cylindrical. Their heads are drawn out to form a short, broad beak. Cossonids are the only weevils that infest wood; other weevils infest grain or growing crops. LIFE CYCLE The adult females lay eggs on or in wood. The eggs hatch into larvae, which develop as they tunnel the wood. The tunneling continues throughout the larval stage, which lasts for months or years, depending on the kind of beetle. The full-grown larvae transform to pupae, which become adult beetles. The adults of many kinds of powder-post beetles bore circular holes to the surface of the wood and emerge; others make oval holes. Some emerge in early spring; others, including the old house borer, emerge in early summer. Mating and egg laying follow. The life cycle of lyctus beetles varies from 3 months to 1 year, depending on the species and on regional differences in temperature, moisture, and availability of wood of high food value. The life cycle of anobiid beetles is sometimes completed in about 1 year and sometimes in 2 years. Most of the bostrichids and cerambycids complete the cycle in about 1 year, but a few of the latter require several years. The old house borer, a cerambycid, requires 5 to 7 years in the North, and less time in the South. In all but a few months of its life cycle, it is in the larval stage. Larvae 3 or 4 years old are often found in the woodwork of buildings only 1 or 2 years old--evidence that stored lumber is a source of infestation. Cossonid weevils complete the cycle in about 1 year. EGG LAYING The females lay eggs on or in wood that satisfies their egg-laying requirements and the food requirements of the larvae. These requirements differ among the species. Hence different kinds of wood are infested by different species of beetles. Lyctus beetles infest hardwoods. Cossonid weevils infest softwoods. Some anobiids, bostrichids, and cerambycids infest hardwoods, and some infest softwoods. For some species bark is an egg-laying requirement; for others it is not. Some anobiids infest moist wood containing decay organisms, which appear to aid development of the larvae. [Illustration: Adult of the southern lyctus beetle.] [Illustration: Adult of the old house borer.] [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.