We are fortunate to have a fair number of these butterflies in our area (Green Lane, PA). The caterpillars feed on spicebush shrubs, sassafras, and tulip poplar which are numerous here. The wingspan of these beauties is 3 to 4 inches. As adults, they readily visit flowers, and we often see them buried inside daylilies with only the wing tips showing.
Their range covers most of the mid to eastern lower 48 states, and our sub-species prefers shaded woods and the margins of the woods.
This pretty girl is identified by her blue iridescence; the males shine greenish.
This picture was taken June 7, 2011.
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Another card is posted with a side view