I apologise for these posts. I hope that someone finds tgem as educational as I do.
This guy is approximately 5cm long with a 1cm long barb on its back end. They seem to feed exclusively on my four o'clock flowers (Mirabilis jalapa) as I have found four others on neighboring plants.
Last edited by BilliGoatsGruff; 10-03-2016 at 05:15 PM.
Reason: Edit: turns out it's a Vine Hawk Moth caterpillar.
It is either a Daphnis Moorei [ Hawkmoth], or a very close relation to it.
They are normally found in Queensland, but maybe there is a variety found in your neck of the woods.
raymo