Butterflies of the Adirondack Mountains:
Clouded Sulphur (Colias philodice)
The Clouded Sulphur butterfly (Colias philodice) is a medium-sized yellow North American butterfly which may be seen in the Adirondack Mountains in upstate New York in early summer. It is also called the Common Sulfur.   Male Clouded Sulphurs have sharply defined black borders on all four wings on the upper side, while the female has yellow spots in the black border. Clouded Sulphurs usually land with their wings closed, so it is difficult to get a clear view of their upper surfaces.   
The underside of the male's wings is yellow while the female's is yellow or greenish-white.  The underside of the wings has a row of small brown submarginal spots. The under side of the hind wing usually has a silver cell spot rimmed by pink.  Spring and fall forms of the Clouded Sulphur reportedly are smaller and less conspicuously marked.  Moreover, both sexes tend to be greenish yellow in the spring and fall, clear yellow in midsummer.  The female has a white form.  This butterfly is difficult to distinguish from its close relative, the Orange Sulfur,  some of which show very little orange.  Yellow-orange hybrids with Orange Sulfurs reportedly occur. 
The Clouded Sulphur lays eggs singly. The eggs hatch into smooth green larvae with a dark stripe down the back and light stripes on the sides.  Caterpillar hosts include plants in the pea family, such as alfalfa and white clover. Adults consume the flower nectar of many plants.  This butterfly is an avid mud-puddler; and swarms of Clouded Sulphurs can often be seen fluttering around a mud puddle.  Sulfurs reportedly fly steadily with little gliding. 
From the ecological standpoint, the Clouded Sulphur is a generalist.  Wide-ranging and adaptable, this butterfly can be found in many different open areas, including fields, lawns, road edges, marshes, bogs, and meadows.   The Clouded Sulphur is absent from dense forests.  It is said to be one of the most widespread and common North American butterflies.  Its range is Alaska south through central and southeast Canada and the US,  including Texas, Western Canada, Southeast, Southwest, Florida, Plains, Rocky Mountains, Eastern Canada, Northwest, New England, Great Lakes, Mid-Atlantic, Alaska, and California. 
Clouded Sulphur butterflies may be seen in our part of the Adirondack Mountains throughout much of the summer. During the summer of 2012, we had Cloudeds in the Paul Smiths VIC Native Species Butterfly House from 11 June to 18 August and another batch in late August-September in the adjacent Butterfly Garden. 
- Susan Grimm Hanley. Interpretive Naturalist, Paul Smith's College Native Species Butterfly House. Species Logbooks.
- Butterflies and Moths of North American. Species Profiles. Sighting record: 6/16/12
- Government of Canada. Canadian Biodiversity Information Facility. SpeciesBank.
- Massachusetts Butterfly Club. Massachusetts Butterfly Species List.
- ENature. Field Guides.
- Iowa State University. Department of Entomology. BugGuide.
- National Audubon Society. Field Guide to Butterflies (New York: Alfred A. Knopf, 1981), pp. 371-372.
- Jim P. Brock and Kenn Kaufman. Kaufman Field Guide to Butterflies of North America (Houghton Mifflin, 2003), pp.60-61.
- Paul A. Opler. A Field Guide to Eastern Butterflies (The Peterson Field Guide Series, Houghton Mifflin Company, 1992,1998), pp. 60-61, 154-155.
- Jeffrey Glassberg. Butterflies of North America (Michael Friedman Publishing, 2002), pp. 76-77.
- James A. Scott. The Butterflies of North America. A Natural History and Field Guide (Stanford University Press, 1986), p. 198-199.
- Donald and Lillian Stokes. Stokes Butterfly Book. The Complete Guide to Butterfly Gardening, Identification, and Behavior (Little, Brown and Company, 1991), pp. 54-57.
- Jeffrey Glassberg. Butterflies through Binoculars. The East. A Field Guide to the Butterflies of Eastern North America (Oxford University Press, 1999), p. 56-57, Plate 8.
- Paul A. Opler and George O. Krizek. Butterflies East of the Great Plains: An Illustrated Natural History (The Johns Hopkins University Press, 1984), pp. 64-65.
- Rick Cech and Guy Tudor. Butterflies of the East Coast. An Observer's Guide (Princeton University Press, 2005), p. 84.