Beneath the horizontal line are the following:
Now for the color differences: Berger clearly shows a brighter, more yellow Akialoa than Frohawk, and a somewhat more colorful and greener bird than that in the print from the Hawaiian Legacy Archive. A search of the internet provided only images of stuffed specimens, no color photo of a live bird. Based on several of these, it appears the colors Marian Berger used are most accurate. This is further substantiated by the fact that the prints in Frohawk's Birds of Hawaii are very so-so.
The Akialoa is now thought extinct. For a while biologists believed there were two subspecies of Akialoa, the Greater and the Lesser Akialoa; current thought is that there was a single species only.
What a beautiful bird; I would love to have seen one in the wild.