How does a beetle larva change into an adult?

Beetles undergo a process called holometabolous (complete) metamorphosis, which consists of four distinct stages: egg, larva, pupa, and adult.12

During the larval stage, the insect feeds and grows, periodically molting its skin to accommodate its increasing size. Once the larva is mature, it enters a nonfeeding prepupal stage before transitioning into the pupal stage.2

The transformation into an adult occurs within the pupa, which is an inactive stage. During this time, larval organs and tissues are broken down, and adult structures—such as wings and reproductive organs—are developed. The pupa typically resembles the adult in form but is soft, pale, and has its appendages and wings folded against its body. When the transformation is complete, the adult emerges by shedding the pupal skin. The new adult then expands its wings to their full size, and its outer skeleton hardens and develops its final coloration.123