I'm no expert, but I can see that they are 'bird drop caterpillars'. There are several kinds of butterflies whose caterpillars disguise themselves as bird droppings in the first instar or two to escape predation. From the looks this cat it's a later instar which I think will probably turn into a Giant swallowtail butterfly. Lucky you! Whoo hoo!!! :-)

Giant Swallowtail...big beautiful butterflies! They use Rue, among other host plants. Congrats! I've seen the black and yellow butterflies a few times this summer, but no caterpillars.

I planted wafer ash for them. Linda_tx8 led me to a place where they were going to be bull dozed down and we rescued several small ones. Wafer ash trees are very slow growing, but that's okay. I can wait. I have another food source for them -- a Satsuma orange tree. I had several caterpillars on it year before last. But so far this year I've only seen one Giant Swallowtail in my yard, and no cats.

As I said -- lucky you.

We've had a bunch of swallowtail and monarch larvae in the gardens this year. Especially in the old fashion section.

I get them on parsley and dill. I keep parsley alive just for them. c

Oooh cool, thanks for the ID. I've seen a few Giant Swallowtail in the yard lately.

It is very interesting to find the host plants for different cats. They all have different likes. Some of the favorites are:

Eastern Black Swallowtails feed on fennel, parsley, dill, carrot, parsnip, and rue.

Gulf Fritillary and Zebra Longwings are common on passion vine.

Monarch butterflies love plants in the butterfly weed family and fennel.

Queen butterflies also munch on the milkweeds.

The Giant Swallowtail prefers citrus and rue.

Painted Lady larvae love borage and members of the thistle family and sunflower.