. An annotated list of the important North American forest insects. Forest insects. wood borers may be divided into three subgroups, namely, powder- post beetles, roundheaded borers, and flat-headed borers. I'OWDER-POST BEETLES The powder-post beetles are short, cylindrical, recldish-brown to black, hard-shelled insects, ranging in length from one-eighth tonearly one-half inch. In the eastern section of the United States there is only one species ^ that causes much damage to the class of materials under considera- tion. This beetle has reddish-brown markings and is about one-fourth of an inch
. An annotated list of the important North American forest insects. Forest insects. wood borers may be divided into three subgroups, namely, powder- post beetles, roundheaded borers, and flat-headed borers. I'OWDER-POST BEETLES The powder-post beetles are short, cylindrical, recldish-brown to black, hard-shelled insects, ranging in length from one-eighth tonearly one-half inch. In the eastern section of the United States there is only one species ^ that causes much damage to the class of materials under considera- tion. This beetle has reddish-brown markings and is about one-fourth of an inch long. (Fig. 8.) It is commonly known as the " red-headed shot-hole borer " and was mentioned years ago by C. V. Riley as doing considerable damage. It works principally in the wood of the hickory and persimmon, although it has been found in other woods. The adult bores through the bark and into the sapwood, making a cylindrical tunnel around the log just under the surface of the wood and at right angles to the grain. (Fig. 9.) The pores or cells of the wood are opened up, and the female beetle can then insert her eggs into them. The original or egg tunnel is usualy bored about 11/2 inches on each side of the entrance hole, although in some cases it may extend in one direction only. The injury can readily be detected by the loose, whitish, dustlike borings which may be found on the bark below the circular entrance hole of the parent gallery. The larva or grub of this beetle has a curved form, some- what similar in shape to that of the cut- worms found in the garden. When it is doubled up the head of the grub is close to the end of the abdomen. (Fig. 10.) This beetle, in marked contrast to the am- brosia beetles, is ex- ceedingly destructive to the wood, both in its adult ancl larval stages. In pieces of wood of small diameter it often extends its gallery or tunnel completely around the section, thus Figure 7.—Boring dust or frass which certain specios of ambrosia bee
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Keywords: ., bookauthorhopkinsadandrewdelmar, bookcentury1900, bookdecade1900
