Gosh I am no expert..however, I believe that's the Cecropia Moth caterpillar.

It's beautiful, whatever it is. What tree/shrub is it on?

It's got a brown spot on top of it's head...I hope it is ok. It is hanging in a cherry tree...not sure what kind of cherry tree, but I have never seen anything like this before.

It's a last instar cecropia moth. I don't know why it's got that brown on its head, but it's undoubtedly about to spin its big cocoon among leaves somewhere, maybe right there.
Congratulations! There's no more beautiful big moth than a cecropia!
Sherry

Callosamia promethia. It is one of the saturniids, but not a Cecropia.

The cat on the left in this picture is a last instar promethea moth, and the cat on the right is a mid-instar cecropia -
{{gwi:485464}}
And here's a late instar cecropia cat-
{{gwi:481526}}
She said her cat was huge - prometheas aren't huge - and it has the round orange knobs on its head that cecropias, not prometheas, have.
Sherry

P.S. It's also got the blue cecropia "shoes" and it's on cherry, a favorite of cecropias.
Sherry

Thanks Sherry...yes it is in a sand cherry tree and right now it is hanging upside down at the end of a branch (and yes, it is very large) ....I can't wait to see it when it comes out. Do they over winter and come out in the spring?? I can't wait that long to see it lol

Karen

It looks nothing like my Promethea cats, that's why I said Cecropia...lol...mine at best, were maybe 2 1/2 inches long. About as big around as they were long! This was one of my Promethea cats before it spun it's cocoon.

{{gwi:510198}}

Maybe it is then. I just did not see any red or orange tubercles--just blue and yellow ones. I don't like the looks of the dark spot that looks like a parasite-induced wound.

It's good to know they'll eat Sandcherry. It looks like the purple leaf type in your photo and I have those in my yard. Yay!
You'll have to wait until spring for it to emerge. I have one in a container now in my house and I've been reluctant to put it back outside. I may try to keep it in my fridge. I'd love to be able to see it.

Christie's right - as far as I know, cecropias are once a year moths.
The cocoon will look something like a brown bag, Karen.
Sherry

Wonderfully informative thread and beautiful photos, all. Sherry, I can't understand why you want a new camera. Your photos are great.

Now I've off to google the Sand Cherry. Maybe it will fit in my small garden!

~Mary

Tomato Worm presents a valid concern. What is that ominous dark patch near it's head?

Do wasps lay eggs inside cecropias too? I have had 4 monarch victims this summer. When they attempted to pupate chrysalides (and one maggot) have fallen out of them. :(

Thanks, Mary, but the pictures on this thread were made with my Canon DigitalElph. I loved the camera, it made great pictures, but after about ?1 - 1 1/2 years? the lens wouldn't come out of the camera when you turned it on. That mechanism gave me trouble for a few weeks before it finally quit.
I would get another Canon just like it, but I read reviews, and in review after review, the camera owner said that theirs did the same thing.
The next camera I bought was also a Canon, but only cost $100, and it takes pictures like it cost $100.
Hopefully, my next camera will be a good one!
Sherry

I am worried about the dark spot too...I have no idea what it is or what happened. I was so shocked to see this in my tree and I also had no idea what they were supposed to look like as I have never seen it before. I hope it is not that eggs were laid in it :( I too have seen maggots come out of my monarch cats and it is disgusting!! thanks for all the comments

Karen

The dark patch is probably melanin in response to some injury. The injury could be anything from a parasitoid to a molting injury. Yes, all insects are attacked by parasitoids. The parasitoid wasps are some of the largest insect groups in the world.

The giant silk moths have been particularly affected by Compsilura concinnata, a tachinid fly released to attack gypsy moths. On the east coast many of the large moths have diminished in large numbers due to this fly.

The location of the brown spot may mean a tachinid fly. Often they lay eggs on the face or head. This keeps the caterpillar from removing the eggs with their mandibles. The only thing to do is wait and see.

Good luck,
Elisabeth