The five spots in that upper short white line on the wing is what makes this a Tanna instead of a Teleus, Brown or Plain Longtail. Otherwise, those four are very similar and often confused. These two were in my garden and are fairly common Skippers here.
And for comparisons with Teleus, Plain & Brown Longtails, browse through all my SKIPPER GALLERIES to see those and many others! 🙂