Wingless insects are small creatures that lack wings and are often found in homes and gardens. The three most common wingless insects are fleas, lice, and silverfish. Fleas are small, dark-colored parasites that feed on the blood of mammals and birds. Lice are tiny, wingless insects that live on the skin of humans and other animals. Silverfish are small, wingless insects that are usually found in damp areas such as basements and bathrooms.