I have just learned this Ascalapha odorata (Black Witch Moth) is not the moth to the pictured caterpillar (frangipani worm) Pseudosphinx tetrio. It is not the Giant Grey Sphinx Moth.

I will continue to try to photograph it.

This is the true Giant Grey Sphinx Moth - Internet photos, not mine:

Cool! I actually had some Sphinx moths around last summer, but they were Manduca Sexta, which had grown from Tobacco Hornworms. Little guys ate my tomato plants.

The wings are usually a pretty good giveaway for Sphinx moths, they all are about the same shape, and look narrower than you would expect for such big moths.

Actually, I'd say that the larger and more colorful a moth is, the more likely it is that you've found a giant silk moth, which are gorgeous, but they all die within a few days and don't really pollinate.

Your moths will have FEATHERED antennae whereas the lepidoptera will have clubbed antennae. As zomb mentioned, most larger moths will not have a proboscis and are unable to sip nectar. They hatch to lay eggs, and die when they run out of energy … unable to feed, which is why they have such voracious appetites as larva …

Here's one I saw on a tree; at a 2014 Bonsai show.

Nice! Looks like a white line Sphinx Moth to me.

That one is called Ascalapha odorata (Black Witch Moth) .... The same one in my original pic above. They are huge and, yes, fly so fast it's easy to mistake them for bats. I also thought it was a Grey Sphinx Moth (see 6/1/2017 post above for pic of that one) at first because I get the voracious caterpillar on my plumeria.