Just when I thought I had the woolly aphids all figured out, I came across this picture in my files. It's not one of the two witch hazel gall aphids (which have birch as an alternate host), because (among other things) the wing venation is totally different. It's not Eriosomatinae, because the adult has a well-developed mouthpart; also, none of those seem to have green bodies or wing venation this complex or antennae this long. The young nymphs, which were feeding on the underside of the leaf, were not woolly. These seem totally unrelated to any of the options I've summarized on the "unidentified woolly aphids" guide page.