Eastern Tailed-blue
Cupido comyntas

f25 @ 1/320s, ISO:2500, Nikon D3S w 105mm macro

"Eastern Tailed-blue," Wikipedia, the free encyclopedia. The Eastern Tailed-blue or eastern tailed blue, also known as Everes comyntas, is a common butterfly of eastern North America. It is a small butterfly that is distinguished from other blues in its range by the small thin tail. Males are generally blue on the upperside of their wings while females are lighter blue to brown or charcoal in coloring, but there are also varieties of purple and pink found in both sexes. The underside coloration ranges from bluish white to tan. There are two or three (outermost one often faint) black to orange chevron-shaped spots on the rear of the hindwings and a trailing tail off the innermost of the spots. The butterfly is 21 to 29 mm (0.83 to 1.14 in) wide with wings outstretched and slightly shorter in length.
Francis A. Crane Wildlife Management Area, East Falmouth, Massachusetts