Every year I find some of these guys in my garden. I blogged about it on my blog
here,
here and
here.
Sorry, my blog is in Dutch, so here you have some of the pictures:
The hole from which the caterpillar came from and some of it's droppings (which are huge):
To give you an idea about the size (in cm)
It's jacket (after a few weeks):
The pupae (found underground when pulling weeds, replaced it afterwards)