The larval caterpillar is also brown, like the adult. They are larger than other families of caterpillars. Seven short white lines run diagonally down the side of the hairless body from the head to its other end. It is a part of the hornworm group of caterpillars thanks to a long spine, or "horn" at the end of its body. As the caterpillar grows and matures, the horn is eventually lost and an eyespot develops instead. This species feeds on the leaves of grapevines and is known to be a pest in vineyards. Virginia creeper and woodbine are other popular food sources for this caterpillar. It is usually seen in August and September.