Nick, same as my other answer, these where not as difficult as some. Well, I take that back… IDing from the upperside is easy, from the underside, not so much. Those shots I had to wait till I got to the computer. But when they rested open winged, I could tell them all apart quite easily. But I did a lot of research, and since I went to Maolin specifically to see these four species, I was prepared. And since there were literally thousands of them, I got a lot of opportunities to practice!
my butterfly collection 
I can’t believe all of these species that are so similar-looking. It must be a nightmare trying to identify them in the field!
Nick, same as my other answer, these where not as difficult as some. Well, I take that back… IDing from the upperside is easy, from the underside, not so much. Those shots I had to wait till I got to the computer. But when they rested open winged, I could tell them all apart quite easily. But I did a lot of research, and since I went to Maolin specifically to see these four species, I was prepared. And since there were literally thousands of them, I got a lot of opportunities to practice!