This is a Baltic Amber inclusions. It is some where between 40 to 50 millions years old. Read more about Caddisflies on Wikipedia.
Credit to the photographer – Anders L. Damgaard. Check out his website Amber-Inclusions.dk and Wikimedia User Page. This file is licensed under the Creative Commons Attribution-Share Alike 4.0 International, 3.0 Unported, 2.5 Generic, 2.0 Generic and 1.0 Generic license.
With Love, TeeTee Ella