This beautiful butterfly is essentially a southern species and is found over a wide range of territory from the Mississippi River to the Atlantic Ocean. It occurs as far north as New Hampshire and Vermont and has even been reported from Alberta, Canada. It is easily recognized by the blue-green clouding of the upper surface of the wings, the general color being velvety black with distinctive rows of yellow spots along the margins of the front wing. These spots are present also on the hind wing where they are almost changed to blue because overlaid with a general cloudiness of this color. On the under surface of the hind wings there are two rows of orange-brown spots, the inner row being nearly crescent-shaped and the outer row oblong. In the living insect the tail projections on the hind wings are usually twisted into a vertical plane at right angles to the plane of the wings. The caterpillars of this species feed upon the leaves of sassafras and spice bush. The distribution of the butterfly appears to be closely related to the distribution of these plants. As is the case with so many of our Swallowtail butterflies, the Green-clouded Swallowtail passes through the winter in the chrysalis stage. Late in spring the butterflies emerge and soon afterward lay their eggs singly upon the leaves of sassafras or spice bush. The eggs soon hatch into lead-colored caterpillars, largely covered with spiny warts. Each caterpillar cleverly makes a protecting nest by eating out a narrow strip in the leaf which frees a flap along the margin that is turned back upon the leaf, making a case in which the larva lives. It spins a silken carpet on one side of the case and rests upon this carpet when at home. During its feeding periods it goes outside and eats the tissues of the other parts of the same leaf. It continues to occupy this first nest for a week or more by which time the rest of the leaf is likely to be pretty well consumed.