When the Large Skipper is sitting with it's wings closed, it can get rather confusing when trying to identify between male and female. Back in 2006 as a newcomer to the world of butterflies, i too would often be totally perplexed as to which was which with the sexes of this species, along with the Small Skippers. After closely studying these two species, i found that the antenna were completely different from the males and the females. I also found that the males have larger eyes than the females in this species, as do many males of other species of butterfly.
The antenna of a male Large Skipper being orange and black
The antenna of a female Large Skipper being black and white