Several other Swallowtail butterflies are found within the limits of the United States, especially in the Far West and along the southern boundaries. Some of these occasionally migrate east or north so that they are collected in the Central states. Thus _Papilio daunus_, _P. oregonia_, and _P. zolicoan_ are all found in the "List of Nebraska Butterflies," published by Mr. H. G. Barber, and the same species have been taken in other states in or near the Mississippi Valley. These and various others are described and pictured in Dr. Holland's excellent "Butterfly Book." _Synopsis of the Swallowtails_ _Tiger Swallowtail_: _Yellow form_ (_Papilio glaucus turnus_). Expanse 3 1/2 to 5 inches. Upper surface of wings bright yellow with each black margin marked with a row of yellow spots. Both sexes throughout its range. _Black form_ (_Papilio glaucus glaucus_). Black all over with blue markings on outer half of hind wings and row of straw-yellow crescents on borders of same. Females only, and only south of about latitude 40 degrees. _Giant Swallowtail_ (_Papilio thoas_ or _Papilio cresphontes_). Expanse 4 to 5 1/2 inches. Upper surface black with two bands of yellow starting at the inner margin of the hind wings and coming together as a row of yellow spots at the outer angles of each front wing. A yellow spot on each black tail. Under surface yellow. _Zebra Swallowtail_. Expanse 3 to 3 1/2 inches. Easily known by the stripes of green upon black and the long, slender tails. The different forms vary in size and in the length of the tails. Scientific names are: Early Spring Form, _Iphiclides ajax marcellus_; Late Spring Form, _I. ajax telamonides_; Summer Form, _I. ajax ajax_. [Illustration: _From a photograph from life by A. H. Verrill_ _See pages 7, 67_ CATERPILLARS OF THE GREEN-CLOUDED SWALLOWTAIL In various stages of growth] [Illustration: _Photographed from life_ _See page 83_ IMPORTED CABBAGE BUTTERFLY] [Illustration: _Photographed from life_ _See page 215_ BLUE-EYED GRAYLING VISITING JOE PYE WEED (Magnified)] _Green-clouded Swallowtail_ (_Papilio troilus_). Expanse 3 1/2 to 4 inches. Black with about seven yellowish spots on outer margin of each front wing and eight marginal spots on each hind wing, those at the ends of row orange, the rest yellowish or bluish. Outer half of hind wings clouded with greenish blue. Under surface black with two distinct rows of yellowish spots on front wings and two rows of orange spots on hind wings.