And Where Did They Go?

Most of my home gardening this summer has involved pulling weeds in the back yard and attempting to keep the container plants watered, but today's temperatures miraculously dipped to the 50s and 60s, so I was able to spend several hours in the yard without either heatstroke or death by mosquitos.
I had the pleasure of finding two of these in the front garden:

Since they were eating a vine rather than milkweed, I assumed they were Swallowtail caterpillars rather than Monarchs, and since there are numerous types of Swallowtail, that's not impossible, but this Wikipedia photo of a Monarch caterpillar looks more like my guests than any of the Swallowtail photos. The plant, they were devouring, honeyvine (Cynanchum laeve), is apparently one of the few non-milkweeds Monarchs will eat.

I was going to photograph my striped tenants in their full glory, but when I returned with the camera an hour or so later, they were gone. I hope they were merely napping out of sight and not eaten by birds.
Speaking of birds, a hummingbird came by around the same time to check out the blossoms on a coleus I had just repotted. The other day I saw a bright yellow bird of finch-like shape in the back yard (I have no idea what it was).
And there are many types of butterfly and bee visible in the yard at any given time.