You can estimate its size when you realize that it's on the palm of my hand.
(Aside to prashanthchengi....that sentence above is a good illustration of when to use "its" and when to use "it's". The possessive pronoun does not have an apostrophe.)
I found that there was a greenish little sphere on the side of the caterpillar; it was not the mouth or the cloacal area, so I could not understand what it could be.
I asked Dr M B Krishna, who said that it might be emerging from a "pod" or egg-case . So, I decided to also ASK (Ask S Karthikeyan). Karthik said that it might be a drop of fluid that the caterpillar had expressed from its mouth; but I told him that this green thing was actually not a liquid, but quite hard. He decided to reserve judgement on what it could be...so there it remains, another tiny, unsolved mystery of Nature!
If anyone can throw any light on this, I'd be grateful...
And meanwhile if anyone can see my heart line and fate line in the photograph and tell me how rich and famous I'm going to be, I'm open to hearing that, too!