A butterfly pupa (aka caterpillar) will form a chrysalis around itself before blossoming into an adult butterfly. Nilanka Sampath / Shutterstock
When the caterpillar is big enough, it enters the pupal stage. This involves forming a chrysalis—or in some species, a silken cocoon—where major changes happen.
Unlike moths, most butterflies don’t spin full cocoons. Instead, the caterpillar often hangs upside down and sheds its final skin to reveal the pupa underneath.
Inside the chrysalis, the caterpillar’s body breaks down into a kind of biological soup. From this, an adult butterfly forms, complete with wings, long legs and compound eyes.
