446 The Moths and Butterflies 



three or four white spots appear; in some specimens the hind wings have 

 a narrow broken border of scarlet on the under side. 



Of the yellows, or sulphurs, the most familiar in the eastern states is 

 Eurymus philodice, the clouded sulphur, expanding i to 2 inches; the 

 wings are pale sulphur-yellow with black outer borders and with a discal 

 black spot on each fore wing and orange spot on each hind wing; in the 

 female the black border of the fore wings is very broad and contains five or 

 six irregular yellow spots. Similar in pattern, but with the ground color of the 

 wings bright orange instead of pale yellow, is the orange-sulphur, E. eury- 

 theme, common through all the West. Both of these species are polychro- 

 matic and polymorphic, that is, show marked variation in ground color and 

 in size, some individuals called albinos being white, some called negros 

 being suffused with blackish; some are very small, others unusually large. 

 A variety of names has been given to some of these aberrations because 

 of their regular appearance under certain seasonal conditions. The longi- 

 tudinally striped green larvae of both species feed on clover. Another com- 

 mon sulphur in the southern and western states is the dog- face, large with 

 pointed-tipped front wings and the yellow color of these wings so outlined 

 by the black base and broad border as to produce a rough likeness to a dog's 

 head seen in profile; a small discal black spot serves as the eye. The south- 

 ern species is Zerene ccesonia (PI. V, Fig. 10), the Pacific coast species Z. eury- 

 dice. The caterpillars, which are green with a whitish longitudinal stripe and 

 a transverse dark line on each segment, feed on various Leguminosae. Another 

 common southern and western species is Terias nicippe, the black-bordered 

 orange (PI. XI, Fig. 2), whose larvae feed on cassia. A striking species 

 is the cloudless sulphur, Catopsila eubule, the largest of the Pierids, expand- 

 ing 2^ inches; it occurs in the southern and southwestern states, its larva 

 feeding on cassia. At the other extreme in size is the dainty sulphur, 

 Nathalis iole, (PI. V, Fig. 7), the smallest member of the family, expanding 

 but i inch; it has the same range and food habits as the cloudless sulphur. 



In the western states occur seven or eight species of the pretty little 

 Pierids known as orange-tips; only one species, Synchloe genutia (PL XI, 

 Fig. 3), is found in the east. All are small and most of them are readily 

 distinguished by the characteristic orange-colored apex of the fore wings 

 as shown in the colored figure of genutia. S. sara, with two named varie- 

 ties, reakirtii and stella, is the commonest western species. The larvae of 

 the orange-tips, so far as known, feed on Cruciferae. 



Perhaps the most striking and admired of all familiar insects are the 

 great swallowtail butterflies. They have an easy, half-fluttering, half-soar- 

 ing flight; their unusual size and their black and yellow (or greenish-white) 

 tiger-like markings make them so conspicuous that they are fascinatingly 

 apparent to the most casual observers. Twenty-one different swallowtail 



