Department of Energy Argonne National Laboratory Office of Science NEWTON's Homepage NEWTON's Homepage
NEWTON, Ask A Scientist!
NEWTON Home Page NEWTON Teachers Visit Our Archives Ask A Question How To Ask A Question Question of the Week Our Expert Scientists Volunteer at NEWTON! Frequently Asked Questions Referencing NEWTON About NEWTON About Ask A Scientist Education At Argonne Cocoon Forming
Name: Peri
Status: N/A
Age: N/A
Location: N/A
Country: N/A
Date: N/A

How do caterpillars make themselves into a cocoon?

Here is a brief description from the page:

"You will often erroneously hear and read that the adult butterfly emerges from its cocoon. Moths spin cocoons of silken threads, often using leaves to help surround themselves.

Caterpillars shed their final skin to reveal a pupa. The outer skin of this pupa hardens to form a chrysalis which protects and hides the amazing transformation that is occurring inside."

From the web page:

"The most complex type of metamorphosis is called complete metamorphosis. It has four distinct form stages: egg, larvae, pupa and adult. The larval stages do not look like the adult at all, and they are often worm-like. Larvae often have different mouth parts and food habits than the adult, and

they often live in places different from the adult. Larvae molt several times and get a little larger with each molt, but there is no gradual development of wings or other adult characteristics. When a fully grown larva molts, it changes into a pupa. The pupa usually does not eat or move around much, but a lot of internal changes take place. When the pupa has made all its internal changes, its skin splits and the fully formed adult emerges. Most insects with complete metamorphosis are winged in the adult stage. The adults do not molt or grow any more. Little flies or beetles, for instance, do not grow to become larger."

J. Elliott

Click here to return to the Zoology Archives

NEWTON is an electronic community for Science, Math, and Computer Science K-12 Educators, sponsored and operated by Argonne National Laboratory's Educational Programs, Andrew Skipor, Ph.D., Head of Educational Programs.

For assistance with NEWTON contact a System Operator (, or at Argonne's Educational Programs

Educational Programs
Building 360
9700 S. Cass Ave.
Argonne, Illinois
60439-4845, USA
Update: June 2012
Weclome To Newton

Argonne National Laboratory