Finally, a Black Swallowtail caterpillar

This summer I seeded my plot in our local community garden with an abundance of food plants for Black Swallowtail butterflies, but my plans for raising a bunch of them were foiled by some freakish weather.  I thought this year would be a total loss in regard to Black Swallowtails.

Imagine my surprise a couple days ago when I went to the mailbox and saw this colorful fellow resting on a twig.  He/she had apparently wandered away from the clump of rue (another BST foodplant) we have planted by the mailbox.

I brought him in to a container on our screen porch, provided some rue and carrot tops, and then after two days of eating and producing frass, I found him like this this morning:

The caterpillar ignored the twigs I placed in the container and chose instead to create its mat of silk on the wall, and has suspended itself via a silken harness (which wraps behind the nonexistent "shoulders" of the cat).  The next step will be to convert that caterpillar body into a brownish pupa.

Addendum:  The chrysalis was fully formed by September 11 -

As of October 6 there have been no external apparent changes; looks like this butterfly is going to overwinter in the chrysalis.