Hawaiian blue butterfly
This endemic Hawaiian blue butterfly was flitting around at the Palila Forest Discovery Trail, on the southwest flank of Mauna Kea. This one is, I think, a female with its bright underside and uniformly brown top.
The butterfly is also known as the Koa butterfly, since its caterpillar feeds on that tree. I don’t think Koa trees are found in the trail area, but ‘A‘ali‘i (Dodonaea viscosa), an indigenous Hawaiian plant, does grow there and that’s another plant the caterpillar will eat.