Plectris argentata is a species of beetle of the family Scarabaeidae. It is found in Brazil (Rio de Janeiro).
Adults reach a length of about 21 mm. They have a light brown, elongated, egg-shaped body. The upper surface is very densely covered with appressed, broad, silvery-grey scales, interspersed with individual white scales. The pygidium and underside are covered with appressed scale-like setae.