You've got to turn it upside down, think owl, and use the thorax as a beak.
And, you are correct, they are scarcely "irreducible." Is that what was in he original post?
No, I just didn't phrase myself well (at all). Yes, in some cases they seem to mimic hawks or owls. What I meant is that they don't want to resemble the bird that they want to keep away, which is how I took the original comments (perhaps I read that wrong), but rather a predator of that bird (which may include other birds).
And yes, the original post was claiming that the moth eyespots are "irreducibly simple" in that a 'partial eyespot' allegedly wouldn't confer any advantage.