Identifying the yellow butterflies seen in fields, forests and backyards around the United States starts by recognizing that apart from some swallowtail species and an occasional brushfoot, all the yellow butterflies belong to the subfamily Coliadinae. With approximately two dozen native species, divided into ten separate genera, sulphurs show some diversity within the larger butterfly family, Pieridae. Almost half of the Coliadinae species, approximately one dozen, belong to one genus, Colias. Most species grow to an above average size, having a two to three inch average wing span.
Individuals interested in butterfly gardens can use a vertical geography rule of thumb when considering yellow butterfly species in the garden. Diversity increases from north to south. Northern gardens might get one or two Colias species on a regular basis. Southern gardens might get species from all ten genera at different times during the year.
This pocket guide to yellow butterfly identification organizes around the ten yellow butterfly genera.
Starting with the Barred-yellow (Eurema daira), the people of the south might see the occasional Eurema in the garden. The picture shows a species with a rather drab looking wing. Darker bars form on the wing during the wet season.
A few fortunate gardeners in the southern areas of Arizona, New Mexico and Texas might be able to draw the Boisduval’s Yellow (Eurema boisduvaliana) to the garden. They are medium sized subtropical butterflies and their larvae feed on Cassias, a common native plant in the pea family.
Primarily tropical species, two Angled-sulphur butterfly species (Atneos) occasionally make their way to the United States.
With a one inch wing span, the Dainty Sulfur (Nathalis iole), measures in as the smallest sulfur butterfly. The caterpillars feed on plants in the aster family, the largest plant genus in the world. The wide availability of plants provides the Dainty Sulfur with an extended range from Central American, north through the Midwestern United States.
It’s also North America’s sole Nathalis representative. The picture highlights its winter form. During the summer, the top and bottom wings show more yellow.
Another one of a kind, the Sleepy Orange butterfly (Abaeis nicippe), represents the Abaeis genus for North America. Common across much of the south, picture two highlights some dark wing patterns on the underwing, a good field identification clue.
Females display more marks than males. Winter colors on both genders appear brighter yellow.
The Lyside Sulphur (Kricogonia lyside), North America’s sole representative of the Kricogonia genus, extends its range to the Southwest, Texas, and occasionally the lower Midwest. The picture presents a side view of the wings, devoid of a pattern, with a hint of green shading on the underside of the wing.
The Southern Dogface (Zerene cesonia), one of two native Zerene species, might also be one of the most common species. Found from coast to coast, in the south, they fly year round in some areas and spring through fall in others.
The Cloudless Sulphur (Phoebis sennae), the most widespread of the four native Phoebis species, spreads its wings from coast to coast.
While male wing color remains yellow throughout its range, female wing color varies from yellow to white.
The top picture shows a female with a wide band of pink around the wing edges. The crooked line of spots on the top wing differentiates it from the Large Orange Sulphur.
The prominence of the pink band along the wing edges varies from specimen to specimen.
Plants in the pea family (Fabaceae), the larval food of the Western Sulphur (Colias occidentalis) anchor their populations across western North America.
A very common butterfly, the Orange Sulphur (Colias euytheme) extends its range across most of the United States. 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.
The Little Yellow butterfly (Pyrisitia lisa), is indeed a little yellow butterfly, along with being the most widespread of the five native North American Pyrisitia species. The two small black spots on the bottom of the hindwing, near the legs, are the key field identification clues for differentiating it from the Mimosa Yellow.
The Mimosa Yellow (Pyrisitia nise) prefer forest habitats. The look of the hindwing changes from season to season, taking on a variety of yellow shades and patterns. The lack of the two dark spots on the bottom of the hindwing (next to the feet) is the main field identification clue.
The caterpillars feed on plants in the mimosa genus of the pea family, explaining the name.
The Tailed Orange (Pyrisitia proterpia) butterfly gets its name from the very small tail-like projection at the bottom of its wings.
Unlike many butterflies, with open wings, the Tailed Orange presents itself in a square rather than circular form. Researchers are debating the status of the Pyrisitia genus, wondering if it should be combined with another Coliadinae genus.