Think of the brown part like a little buggy hardhat. That shell protects the soft critter within from insect and pesticide attack. (but not my fingernail!)
We have a similarly protected insect on our eucalyptus trees. The little psyllid within spins a sugar-sap cone that foils predator bugs.
Last edited by czygyny; 09-03-2013 at 05:05 PM..
Reason: clumsy syntax