This caterpillar is hanging out in the yarrow. To identify it I looked up the plant it was eating, Achillea. The Painted Lady butterfly is listed as having Achillea as its host plant, and by gum I found a web photo of unmistakably this caterpillar identified as a Painted Lady, larval stage.
The caterpillar pretends that the top of this photo is the head, except you can see that those are pseudopods prolegs on that end. The six insectile thoracic legs are at the bottom of the photo, along with the real head.
I thought this picture was remarkable because you can clearly see the holes in its abdomen that the caterpillar uses instead of lungs. Those two bottom spiracles are visibly exhaling in this photo. And apparently this complicated little creature will resolve into this graceful Painted Lady
(the butterfly photo is not mine). That caterpillar plans to turn my yarrow into butterfly wings. Now that’s alchemy.
Your photos are amazing - the detail is incredible!