The pupa is a resting stage for the beetle. Have you ever seen a butterfly crysalis or a moth cocoon? If you have, then you have seen a pupa. A beetle pupa doesn't look like crysalis or a cocoon, you can often see the beetle's legs. In fact, if you saw one, you might think the beetle pupa was just a dead insect.
For some beetles, the pupa stage lasts for just a few days. Other beetles stay in this stage for several weeks or months. At the end of this resting stage, the pupa molts and the adult beetle emerges.