Brephidium exilis, commonly known as the Western Pygmy Blue, is the smallest butterfly in North America and one of the smallest in the world. It belongs to the family Lycaenidae and has a wingspan of only about 12–20 mm. The upper side of the wings is typically brown with a subtle bluish sheen near the base, while the underside is more distinctive—pale gray or tan with rows of tiny black spots, often accompanied by a hint of coppery or bluish scaling near the body. Despite its size, it can be quite active, fluttering close to the ground. Adults are often seen low to the ground, visiting very small flowers or resting on vegetation.