There are three similar-looking skippers known as the "three witches": Dun Skippers, Little Glassywings, and Northern Broken-Dashes. I have only seen the first two species in our area. The individual at left is a Dun Skipper. Male Dun Skippers have unmarked chocolate brown wings. They often have a golden color on the top of their heads, which is a good field mark in fresh individuals. 

Dun Skippers, particularly the females, sometimes have a few faint white spots on their wings. 

Dun Skippers are usually unmarked brown below, although they can sometimes have a faint band of small white dots. Dun Skippers typically fly from June through September. 

Little Glassywings can be distinguished from Dun Skippers by the large white squares on the upper surface of their wings. 

Little Glassywings usually have a band of white spots on the ventral surface of their wings (sometimes this band is faint). Also, Little Glassywings have a white-colored patch on their antennae, just below the antenna club. 

Little Glassywings fly from June through August. (Note that Little Glassywings are very difficult to distinguish from Northern Broken-Dashes if you can only see the sides of their wings like this. Northern Broken-Dashes lack the large square glassy spots above. They have narrow, elongated rectangular markings instead.)