Leonard Weber

December 13, 2023

This series highlighting 23 of the butterflies seen in Eliza Howell Park was started in January 2023. The last ones are scheduled to be posted before the end of December 2023.

Orange Sulphur is a common park butterfly, one that can be seen flying quite late in the fall. It is typically present until the end of October.

There are two Sulphurs that are regularly present in Eliza Howell: Orange Sulphur and Clouded Sulphur. They look very similar, requiring a clear look — or the review of a photo — to tell the difference.

Both Sulphers have dark borders on the upper side of their wings, but because they rarely open their wings when not in flight, the borders are not usually seen clearly.

Orange Sulphur often shows a little orange on the underside of the forewing.

Sometimes, when the light is right, it is possible to see the dark border showing through the closed wings.

Orange Sulphur has a wingspan of about 2 inches. It is present from spring to fall, spending the winter in the chrysalis stage. It comes eagerly to a variety of wildflowers in the open areas of the park.

As is clear from the above photos, Orange Sulphur is predominantly yellow (no doubt the reason this group is called “Sulphur”). It took me a few years of butterfly watching before I realized that sometimes the Sulphur is greenish white instead of yellow.

Some (but not most) females are more white than yellow. This is also true of Clouded Sulphur and the experts that I consult for identification expertise caution that it is virtually impossible to tell the difference in the field between the white form females of the two species.

In July, I took this photo of a white female as it was just starting to fly, catching the black border on the open wings.

Except for the white females, it is possible, with the use of a good field guide, to tell the difference between an Orange Suphur and a Clouded Sulphur most of the time.

It is not necessary, of course, to be fully secure in identifying which Sulphur is the one on the flower in front of me in order to enjoy the sight and appreciate the butterfly – flower connection.