THIS IS NOT AT ALL RECOMMENDED!!!
This is a method of determining whether a cocoon is a male or female, but not a very good one.
If you still feel this needs to be done, make sure you do it VERY carefully!
You should use small sewing scissors and cut through the silk casing very slowly.
- You may unintentionally cut into the pupa either making the moth deformed when it emerges, or even worse kill it.
- The silk casing helps the moths hold in moisture, when it's removed, they tend to dry out and die (especially if you have them stored in the fridge over the winter).
- If they are free of a casing, it makes it easier for predators to reach them (squirrels, mice, chipmunks, etc.)and carry them away.
DO THIS AT YOUR OWN RISK!!!!