Seen at east end of range, and could be an immature male because of the whitish belly. I came across Ridgely's first book of Panama birds, and this is the bird then called the Fork-tailed Emerald. The female has a dark spot behind the eye, and a white-tipped tail (as do most Emerald females), and there is a photo in my user album of this bird. The taxonomic status was then and is probably still in flux.