The Sphinx adult is a large Grey moth. The other pest is the huge tomato hornworm. It is green and white and is also called the five-spotted hawkmoth. The adult moth is more colorful than the Catalpa Sphinx. Both pests can be used to study insect life stages.
Youngsters can watch the worms pupate and turn into moths.
By the way the best way to control tomato hornworms is to hand pick them.