Orange Sulphur Butterfly - Colias eurytheme
Butterflies and Moths (Lepidoptera) / Butterflies (Papilionoidea) / Whites and Yellows (Pieridae) / Sulphurs (Coliadinae) / Colias
Common name: Alfalfa Butterfly
Live adult butterflies photographed in the wild at Winfield, Illinois, USA.
 

Orange Sulphur Butterfly - Colias eurytheme
Orange Sulphur Butterfly nectaring

The orange sulphur (sometimes misspelled as sulfur) butterfly had a banner year in 2002. These butterflies, along with their nearly identical cousins, the clouded sulphurs, were everywhere by the thousands. 2003, 2004, and now 2005 do not look to be good for these beautiful creatures. It's now July first and I've only seen a very few. (Footnote, June 2007 - the orange sulphurs have never reappeared in anywhere near the numbers of 2002).

Orange Sulphur Butterfly
I had to capture one to see the dorsal wing markings. It was released unharmed. (Minus a leg or two).

Habitat: Open spaces, meadows, fields, roadsides, streamsides.
Life cycle: Eggs are laid in clusters on leaves of asters. Larvae feed on aster foliage. Caterpillars are brown with yellow bands and many branching spines; last brood overwinters. Chrysalis is mottled gray, yellow and brown. There are usually several broods per season.
Range: Yukon to Newfoundland to southern Mexico

Orange Sulphurs - Mated Pair, Male on left
Orange Sulphurs - Mated Pair, Male on left