Hungry caterpillars, 2008 edition

I enjoyed my experience with the black swallowtails last year, so I decided to see if I could replicate my success with monarchs this year. Last month I purchased and planted a small milkweed plant in my garden expressly for this purpose.

It looks like it worked:
(click on any picture for a larger version)
I don't know if these caterpillars are the offspring of butterflies passing through on the way back from Mexico (click here to see a cool monarch spring 2008 migration tracking map) or if they came from monarchs that overwintered here in Houston. At any rate, the guys in my hand are obviously late instar caterpillars that are probably about to pupate. Good thing, too; my little milkweed plant can't take much more abuse! Maybe I should go get another one?

I've planted more dill and some parsley in my garden as well, so hopefully I'll also get more black swallowtail caterpillars to appear sometime this spring.