That is EXACTLY what the worms look like. All about the same size, two inches. They also blend so well into the buds. I put one of the plants in the dark last night and only found one caterpillar on either of the plants last night. My 3rd biggest bud on the plant has finally worn the stem down and is barely standing up and not dragging the floor. Thanks to caterpillars trying to hollow out a couple stems.
Last night I put some BT on my herb garden that was getting pestered, and I'll know how that worked in a couple days. I do know I found two dead butterflies in the yard. My daughter would not be happy if I became the murderer of butterflies.
I saved 4 of the bud worms and have them under lock and key. I gave them an assortment of basil, jasmine, oregano, sage, and mint and in two days the morphed all the leaves into little black pellets of poop. Tomorrow I will be sectioning them off and starting the trials :}