Sulphur Butterflies: Colias Yellow Butterflies (Coliadinae) Yellow Butterflies White Butterflies Types of Butterflies Sulphur identification may or may not be difficult, depending on the species or genus in question. Colias species share many physical characteristics. Because most Colias species have non-overlapping, geographically limited ranges, a limited time investment usually proves sufficient for identification purposes. The Orange sulphur and Clouded sulphur represent exceptions to the rule. Population of both species exist from coast to coast, and both species look very similar. The species also are known to hybridize, making field identification fairly difficult without a top and bottom wing views. Wing tops are yellow with black stripes that are visible as dark borders from underside of the wings. Additionally, a distinct white spot, located in the middle of the bottom wing, is visible during an examination of the underside of the wings. Usually the Orange Sulphur wings display shades of orange. Females in both species also have a white wing form. Without a top and bottom view of the butterfly in the top picture, the identification of it as an Orange Sulphur must be tentative. Plants in the pea family (Fabaceae), the larval food of the Western Sulphur (Colias occidentalis) anchor their populations across western North America. © 2008-2011. Patricia A. Michaels. All Rights Reserved.