Who Am I?

Looking for a last minute photo. First I find the bright yellow gladiolus, with their complicated blossoms. Turn to the left and see a swallowtail caterpillar getting fat on the parsley. Nearby is a younger one, maybe just ready to shed its black jacket for a brighter one. And then bam, there’s something brand new on the petunias, a very long brown caterpillar/worm. And another, and another. Too many to be benign, is my thought, but I leave them there and try to get an ID on line, but no cigar. They are voracious on the petunias; I should have noticed earlier. So, anybody know what this is?