About Thoressa masoni (Moore, 1878)
Thoressa masoni, commonly known as Mason's ace, is a butterfly species belonging to the family Hesperiidae. It was described by Frederic Moore, originally published in 1878 under the original publication citation Moore, 1878. This species is found within the Indomalayan realm, specifically in Burma, Thailand, Laos, and Vietnam. On the upper surface of its hindwing, the discal area bears one or more distinctly defined yellow spots, a feature that sets it apart from Thoressa honorei. Among these spots, the one located at the cross-vein is the largest and brightest in color.
