From the U.S. Postal Service announcement on November 17, 2020:
From the USPS: The Colorado hairstreak graces the eighth nonmachinable butterfly stamp for use on irregularly sized envelopes, such as square greeting cards, invitations or announcements. The stamp art is a highly stylized, simplified image of a Colorado hairstreak (Hypaurotis crysalus). Artist Tom Engeman created the stamp art. Art director Derry Noyes designed the stamp.
Here is a Dragon Card first day cover showing the previous 7 stamps in this series:
Additional information will be posted below the line, with the most recent at the top.
Updated August 31st:
After the August 29th rate increase, this stamp only covers the non-machineable rate and has a price of 88¢.
Updated April 6th:
The Scott catalogue number for this issue is 5568.
Updated March 3rd:
The only first-day postmark for this issue is the FIRST DAY OF ISSUE “killer bar.”
Updated March 2nd:
[from USPS — Ceremony Details] [click pictures for bigger version]
Colorado’s Hairstreak Butterfly Featured on New Stamp for Irregularly Shaped Cards
WHAT: The shimmering purple of the Colorado hairstreak butterfly will be commemorated by the U.S. Postal Service as the eighth stamp in the non-machineable butterfly stamp series.
The virtual dedication event for the Colorado Hairstreak stamp is free and open to the public. News of the stamp is being shared with the hashtag#ColoradoHairstreakstamps.
WHO: William D. Zollars, Board of Governors, U.S. Postal Service
Dr. Paul A. Opler, Professor, Department of Agricultural Biology, Colorado State University
WHEN: Tuesday, March 9, 2021, at 11:30 a.m. EST
WHERE: The virtual stamp event will be hosted on the U.S. Postal Service Facebook and Twitter pages.
RSVP: Please visit usps.com/cohairstreakbutterfly for details of the virtual stamp dedication ceremony.
BACKGROUND: Colorado’s state insect, the vibrant Colorado hairstreak, lives among oak trees in that state and the rest of the Four Corners states — Arizona, New Mexico and Utah — as well as eastern Nevada, southern Wyoming and northern Mexico.
Colorado hairstreak caterpillars hatch in the spring from eggs laid the previous autumn. Plump and green with white fuzz, they feed on the tender new leaves of their host plant, the Gambel oak (Quercus gambelii), also known as the “scrub oak.”
After metamorphosis, the butterfly emerges from its cocoon in late spring or summer. The butterflies dart in and out of the tree’s branches, feeding on the tree’s sap and fallen raindrops. Mature males look for females receptive to mating. Later, the female lays her eggs singly on the host plant and the cycle of life begins anew not far from their ancestral home. In its entire life, the Colorado hairstreak may travel no more than a few yards from where it hatched.
These colorful square non-machineable surcharge stamps were developed in collaboration with the greeting card industry and will be issued in panes of 20 for use on irregular-size envelopes, such as square greeting cards, invitations or announcements. The words “NON-MACHINEABLE SURCHARGE” on the stamp indicate its usage value. The stamp is being issued at the current rate of 75 cents and, like a Forever stamp, this stamp will always be valid for the class of mail printed on it.
Updated February 1st:
Formats corrected in earlier entry. There will be just the one, a pane of 20.
Updated January 29th from the Postal Bulletin:
On March 9, 2021, in Estes Park, CO, the United States Postal Service® will issue the Colorado Hairstreak stamp (Non-denominated priced at the Non-machineable Surcharge 
rate) in one design, in a pressure-sensitive adhesive (PSA) pane of 20 stamps (Item 121200). This stamp will go on sale nationwide March 9, 2021, and must not be sold or canceled before the first-day-of-issue.
The Colorado hairstreak graces the eighth non-machineable butterfly stamp for use on irregularly-sized envelopes, such as square greeting cards, invitations, or announcements. The stamp art was created digitally using images of preserved butterflies as a starting point. The result is a highly-stylized, simplified image of a Colorado hairstreak (Hypaurotis crysalus) rather than an exact replica. The Colorado hairstreak, that state’s official insect, is not attracted to flowers. The small, shimmering, purple butterfly perches in oak trees in the Southwest, sipping sap and raindrops. Tom Engeman created the stamp art. Art director Derry Noyes designed the stamp.
