"Dark blackish brown both above and below, the little glassywing has a series of distinct, translucent white spots on both surfaces of the forewing. The largest central spot just below the stigma of the male is elongated, the corresponding spot on the female is square. The hind wing beneath often has a faint purplish or rusty gloss, and there is usually an indistinct band of pale spots ... the little glassywing has a white area on the antenna just below the club ...." (John L. Tveten & Gloria Tveten, Butterflies of Houston & Southeast Texas, p. 244.)

Skippers can be difficult to distinguish, but this appears to be the Little Glassywing. I believe that I see the white below the club on the antennae, as well.
I have noticed that some skippers appear to have eyerings (as some birds do), and others do not. This skipper and the Tvetens' Little Glassywing lack the eyerings. But compare their Sachem Skipper (246) & Brazilian Skipper (260), which do have the eyering.

Picture taken with a Nikon D90, using a Nikon 200mm, f/4 micro manual focus lens.

November 3, 2012.