The head of the caterpillar is rounded with the mouth underneath. It does not need to make large, sweeping movements in order to chew down a leaf. The tail end of the caterpillar, by contrast, is quite active, frequently dabbing stems and branches, often leaving deposits of green feces. This behavior may trick predators into believing that it is the head. Losing a bit of flesh on the back end might not mean imminent death for the caterpillar. The spiky projection on that end may aid in thwarting attacks by a bird or small mammal.
Tobacco Hornworms, as the caterpillars are called, resemble Tomato Hornworms. Both caterpillars are hairless and green with plump bodies and have spiky 'horns' at their rear. The Tobacco Hornworm, however, has seven white diagonal stripes while the Tomato Hornworm has eight white V-shaped stripes. The caterpillars are often used by certain species of wasp to feed young. Female wasps lay white eggs, which resemble large grains of rice, on the backs of the helpless caterpillar. These eggs hold wasp pupae that will feed on the living caterpillar, slowly killing it as they grow and develop. See what a Tobacco Hornworm looks like when heavily infested by clicking here:
Adults are called 'tobacco flies' even though they are moths. They are most active from midsummer to late autumn. Adults drink the nectar from honeysuckle and petunia flowers. The Tobacco Hornworm Moth has six pairs of yellow (or orange) spots on of its furry abdomen. The wings are hairy and mostly mottled patches of brown and black save for a bit a yellow on the forewings.