I found this on a plant in my backyard. What is it? It was really small; I almost needed a zoom lens to even see it.
Lucky, you! You have active biological control in your garden. Those are the stalked eggs of green lacewings. Their youngsters are very efficient, and voracious, predators (killers) of aphids.
People seldom see the filmy green adults because they tend to fly at dusk or later. At my place in Portland, OR, I see them throughout the winter when they come to our patio light.
For more information, see UC IPM's article on green lacewings.