The big beautiful moths don't have much of a problem finding host plants. Really, no big mystery.

The moths that emerge from those pupae usually do so before the tomato plants go in. The moths are active nectar feeders. The moths that lay eggs on your tomato plants (and there may be many) can come from afar. Sorry.

Learn to look for and identify the little pearl like eggs on the leaves. Squish them on a regular basis and you'll not have any catetpillars.

Thanks for your reply, rhizo. Over the years I have seen big moths (ok, I'll admit, they are beautiful) around my tomato plants, but until now, I have not put two and two together.
What surprised me was finding the pupae in a bed that has been covered since last fall.
Since I don't use any chemicals at all in my beds, I will use your suggestions.
BTW, I put the pupae/ catetpillar in the compost bin, so in one way or another it will be useful.

I hope you gave it that little squish first so you weren't just tucking it back in bed!

GailWright , no " squish". We have city compost, so it will have a ride from Silicon Valley to Gilroy, CA. There it will enter the compost heap unless it can figure out how to escape before it reaches the end. Gilroy has a lot of tomato plants.