Today when I got home from work there was an adult Luna Moth on my front step. Luna moths are one of the most unusual and beautiful of the North American moths known as Saturnidae. They are well known for their green-yellow colors and long tails, and although they are often seen in pictures, they are a real surprise when found in nature. Although they are common throughout the eastern U.S., their night flying habits and short life span as an adult moth, only about 1 week, combine to make them a rare find. The Luna moth, with a wingspan of 4.5-5.0 inches, is one of the largest moths in North America and is very common in many of the eastern states from Maine all the way to Florida. They usually are seen less as you go westward to Texas and the Great Plains. It is also found in southern regions of many Canadian provinces such as Nova Scotia, New Brunswick, Quebec, Ontario, Manitoba, and Saskatchewan.
NOTE: this information was copied from http://www.ivyhall.district96.k12.il.us/4th/kkhp/1insects/luna.html