These are called "Double Gees" down here in Oz. My Dad used to wrap a couple in cotton wool and then put them into empty matchboxes. Right up until the 90s he used to sell them to visiting US Navy sailors on RnR as "Mountain Devil eggs" (the Mountain Devil being a very striking native species of lizard down here). He even gave the sailors instructions on how to hatch the "eggs"!! My Dad had great fun doing this, making a bit of cash on the side.