June 19

A butterfly emerging from a chrysalis Photo Credit: Clipart.com

Science Fact

A Chrysalis Is Not a Cocoon

Despite a common misconception, a chrysalis is not the same thing as a cocoon.

Both moth and butterfly larvae are commonly called caterpillars. They grow by shedding their skin. When a caterpillar is done growing, it begins its change into an adult butterfly or moth.The caterpillar finds a safe place and attaches itself using a silky thread it spins. It sheds its skin one last time and its new smooth outer skin hardens to form the pupa. Another name for the pupa is the chrysalis.

Both moths and butterflies form chrysalides. However, only a moth caterpillar (and, to be completely accurate, not even all of them) spins itself a silky, but tough outer casing before it sheds its skin that final time. It is that outer casing that is called a cocoon. (Incidentally, silk thread comes from silk cocoons.) If you were able to see inside the cocoon, the moth caterpillar would be undergoing the same transformation into a chrysalis as the butterfly caterpillar does out in the open.

Check out some more moth and butterfly resources from Science NetLinks:

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