The bacon or larder beetle (Dermestes lardarius) is roughly 7 to 9 millimeters in length. The rear of the body is pale with black spots, while the rest of the body dark brown. The larvae feed on leather bindings and, when fully fed, bore into the text blocks of books to construct a pupation chamber.

The bread or biscuit beetle (Stegobium paniceum) is a small (2 millimeters) reddish brown insect with very small larvae. The larvae feed on starch materials, especially the rice or flour paste used on endsheets and book spines. A borehole of approximately 1 to 2 millimeters runs parallel to the height and width of the book.

The cigarette beetle (Lasioderma serricorne) is a small, light-brown flying beetle that commonly infests books. The beetle's larvae are one of the types popularly known as bookworms, with eggs laid on the spine of a book and along the edges. Immediately upon hatching, the larvae tunnel under the binding cover, especially down the spine area. The insect then proceeds to tunnel up to 10 centimeters into the paper text, where it pupates into an adult beetle. The adult leaves a round exit hole, as well as powdered paper on the shelf. One of this beetle's favorite foods is dried flowers and spices; these should not be brought into the library.

The larvae of the drugstore beetle (Stegobium paniceum) are also often referred to as bookworms. This beetle is found in moist storage areas, and the larvae can actually tunnel all the way through books, from one cover to the other. As with the cigarette beetle, piles of paper powder signal that this insect is active.