Alfalfa Butterflies of Southeast Colorado

Description: The Common or Clouded Sulphur Butterfly (Colias Philodice) and the Alfalfa Butterfly (Colias eurytheme) are difficult to tell apart even under magnification.

Published: 10/09/2021

Byline: Hart

Alfalfa Butterflies - The Common or Clouded Sulphur Butterfly and The Orange or Alfalfa Butterfly

-Can you tell the difference between the two?

Colias philodice (yellow)

Colias eurytheme (orange - females look green)

The Common or Clouded (sometimes Cloudless) Sulphur Butterfly (Colias philodice) and the Alfalfa Butterfly (Colias eurytheme) are North American butterflies in the family Pieridae, subfamily Coliadinae.

Both species are prominent in Southeast Colorado during late Spring, Summer and early Fall. The males are nearly indistinguishable from each other, but the orange Sulphur females stand out among their yellow counterparts.

(Female Orange Sulphur)

According to The Field Guide to Insects and Spiders of North America by Evans, this is a female orange Sulphur, Colias Eurytheme. They're also called the Alfalfa butterfly.

Mike Barnhart (Clouded Sulphur)

The Clouded Sulphur is also called the Common Sulphur. The males of both species are quite similar and are yellow in color, often found together and in similar habitats.

(Clouded Sulphur foreground, female Orange Sulphur background)