Mecynorhina polyphemus is a large scarab beetle of the subfamily Cetoniinae found in dense tropical African forests, sometimes called the Polyphemus beetle.

It is a frequent feeder on fruits and sap flows from tree wounds.

The third instar constructs an ovoid cocoon for metamorphosis and attaches it to a solid surface.

In captivity, the instar may attach the cocoon to a glass container wall allowing the opportunity to view the transformation.

The female has a shiny surface texture, reflective prismatic coloration, and no horns.