When there is a lemon tree, there is a caterpillar. Unless someone have put toxins in the plant. The caterpillar looks so stunning and enchanting, with its skin of gree color and some brown lines. They are very steady to take photos but it is just hard to maintain the focus. I did try to take caterpillar and the crazy thing is I tried it to the caterpillar the same to yours. Exactly the Papilio demodocus. Im glad you did not bother to take it and throw it, just like what ignorant folks do. The leaves might be ripped and done but at least you gave way for nature to operate. Mercy is what it takes to not bother it. He is hoping to be greeted of mercy.❤️