(Left) Caterpillar ready to pupate (Right) Pupa casing can be yellow, green or brown
Pipevine Swallowtail caterpillar resting on grass stem late afternoon. Its color can indicate its host food plant. This mostly red caterpillar has fed on Aristolochia watsonii: Desert Pipevine.
This Pipevine Swallowtail caterpillar is black with red spots because it feeds on Aristolochia fimbriata, White Veined Dutchman's Pipe Vine, (shown in picture).