Two of these butterfly-shaped books placed on small wooden tables allow visitors to identify the butterflies present. A species list based on these books is included below in the comments.
The butterfly identification books, pictured above, list a total of 34 species, listed below, as being potentially seen in the Winter Garden. Personally I've never seen more than, say, 6 to 8 species during any given visit. Some species, like the blue morphos and the paper kites, I have seem during each visit and they seem to present at all times. Whether the other species are just hiding or whether not all species are present at all times and the species composition changes throughout the "butterfly season" depending on supply or other factors, I do not know.