Cloudless Sulphur

The Cloudless Sulphur (Phoebis sennae) butterfly is a member of the Pieridae family of butterflies that also includes Whites. This species is mid-sized and has wings that range in color from lemon yellow to pale butter-cream yellow to a nearly sap green hue. This species is seasonally dimorphic which means that individual butterflies are know to have different coloration that change with seasons.

A wide-ranging species, the Cloudless Sulphur can be found from South America north into Southern Canada. They deposit their tiny white eggs on plants in the cassia family and the eggs mature to a pale orange color before hatching about six days later. The larvae are a brilliant green color with a long yellow horizontal stripe and groupings of black dots unless the caterpillars are dining on cassia flowers in the fall which turn the caterpillars bright yellow.

Cloudless Sulphurs are sexually dimorphic which means that males and females have different wing patterns and coloration. Males have upper wings that are clean yellow and have very few markings. Female adults have black edging on their wings and have larger markings on the undersides of their wings than males. Also, females tend to be paler in color and have wings that can appear pale yellow or close to white.

Male Cloudless Sulphurs are one of the butterflies that are more likely to be found ‘puddling’ or drinking from sand and mud to collect water that is laden with salts and minerals. These nutrients help the male butterflies replenish minerals and salts that are used up in the sperm package during mating.

Many sulphur butterflies are difficult to identify but the bold plain color of the Cloudless Sulphur makes it easier to pick out than other species.

The genus name Pheobis derives from the Greek word phiobos meaning "pure" or "radiant”. The species epithet of sennae refers to the host plants for the butterfly. Senna is a common name for species of cassia upon which these butterflies lay their eggs.