Clouded Sulphur
Colias philodice Godart, [1819]

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Diagnosis: This clear-yellow butterfly has sharply defined black borders to all four wings on the upperside in the male. The female has yellow spots in the black border and there is also a white female form. The underside of the wings has a row of brown submarginal spots. The hindwing underside usually has two silver cell spots rimmed by pink. Wingspan: 32 to 54 mm.

Subspecies: Subspecies philodice is found throughout most of the North American range. In southern British Columbia, subspecies eriphyle is found. Subspecies vitabunda, which occurs in Yukon and Alaska, has narrower black borders and mostly white females.

Range: The Clouded Sulphur is one of the most widespread and common North American butterflies. It flies in all provinces and territories and appears to be absent only from Labrador, the Arctic, and northern Quebec. It ranges north to the Arctic Ocean in Yukon.

Similar Species: The Clouded Sulphur and the Orange Sulphur (C. eurytheme) can be distinguished from other sulphurs by the underside of the hindwing. The central silver spot has two red rings around it, there is usually a satellite spot, and there is a row of three to five dark spots near the margin. On the upper surface philodice is yellow with a dark yellow spot in the centre of the hindwing. Colias eurytheme almost always has some orange on the upper surface and an orange spot in the centre of the hindwing. The colour of the hindwing spot usually allows white females of these two species to be identified. [compare images]

Early Stages: The reddish-coloured eggs hatch into smooth green larvae with a dark stripe down the back and light stripes on the sides. They feed on a variety of legumes (Fabaceae), particularly clovers and Alfalfa.

Abundance: Throughout most of its range, this butterfly is common to abundant. It reaches its peak in numbers in the late summer and early fall.

Flight Season: There are two or more overlapping broods each year. Colias philodice is seen on the wing in most of southern Canada from May into late October. In Newfoundland it is recorded as an adult in July and August.

Habits: For many people the image of butterflies is a swarm of yellow wings fluttering up from a mud puddle along a country road. This is often how the Clouded Sulphur is encountered, for it is an avid mudpuddler. They can also be seen in clover fields or along roadsides, often stopping to sip at blossoms. The growth of forage-crop production for livestock across North America has greatly expanded the range and numbers of this butterfly.

© 2002. This material is reproduced with permission from The Butterflies of Canada by Ross A. Layberry, Peter W. Hall, and J. Donald Lafontaine. University of Toronto Press; 1998. Specimen photos courtesy of John T. Fowler.

The Toronto Entomologists' Association thanks Agriculture and Agri-Food Canada for providing the content and computer code for this web page.