Butterfly fans rejoice! In 2013, the U.S. Postal Service will issue Spicebush Swallowtail, the third butterfly stamp for use on large greeting card envelopes and other mail of non-standard shapes and sizes.

Envelopes for many large cards requiring the additional postage will feature a silhouette of a butterfly to suggest the use of this stamp. The Spicebush Swallowtail First-Class Surcharge Rate stamps will be issued in sheets of 20 stamps.

Nationally acclaimed artist Tom Engeman created the design on a computer, using images of preserved butterflies as a starting point. The result is a highly stylized, simplified image of a spicebush swallowtail rather than an exact replica. Engeman has designed numerous stamps for USPS, including the previous First-Class Surcharge Rate stamps featuring butterflies: the 2010 Monarch and .