Pacific Forktail (most of abdomen black) female (abdomen S8 blue above but S9 only partly blue) andromorph (blue on head and thorax). The lower individual has broken antehumeral stripes (trending toward the four isolated spots of a male), but no blue on S9.

Dozens of these (12 in my surviving photos, mostly immature females) were perching and moving around the woods across the path from the lake.

Environment: freshwater lake and creek in beach sand, about 1/3 mile from the ocean.