Which of the following best describes the adult American spider beetle's appearance?

The adult American spider beetle is characterized by its globular abdomen that is often covered in fine hairs. This particular feature sets it apart from other beetle species, as it gives the spider beetle a distinctive appearance that resembles a small spider, hence its name. The hairy texture can provide camouflage and may help the beetle evade predators.

In terms of its overall anatomy, the American spider beetle does not possess flattened bodies or long wings, making the flattened body description inaccurate. Additionally, while some beetles can be brightly colored or have large eyes, the American spider beetle tends to have a more subdued coloration that emphasizes its round body form. Lastly, the beetle does not have transparent wings with dark spots, which is a characteristic seen in different beetle species but not in the American spider beetle itself. Thus, the description of the globular abdomen covered in hairs accurately captures the defining features of this insect.