I'm really into butterflies right now, especially little tiny blue ones. Saturday I went to the PVIC (Point Vicente Interpretive Center) again to see if I could find the Acmon Blue butterfly to compare it with the El Segundo Blue. It was another beautiful day. Not too hot. Not too windy. But by late morning, I hadn't seen a single small butterfly. Then one pair obliged me by flitting around the Coast Buckwheat I was observing. These guys are really tiny! No bigger than 1/2 an inch across. It's good exercise for your eyes to try to follow them around.
OK, so now comes the hard part, trying to identify them. As with most of these butterflies, the blue part is on the top and the males usually have more of it than the females. But interestingly, it is the underside that tells the story. I think this pair was the Acmon Blue and here is why. In looking at many websites and photos, and reading many descriptions, I noticed that the Acmon tends to be cleaner and neater especially on the underside. The El Segundo Blue (ESB) has a smudgy gray appearance especially towards the body. The orange on the underwing of the Acmon is in a nice neat pattern (usually) or there is less of it, and on the ESB it is smeared. The black dots or squares are bigger on the ESB, especially on the forewing. One web page that compares the Acmon to the Smith's Blue Butterfly, mentions that the Smith's has a black-and-white checkerboard pattern along the edge of the upper wing. I noticed that the ESB has this, too, to some extent. The Acmon again is cleaner and the edge, when you can see it, is all white. It seems the ESB is closer to the Smith's than it is to the Acmon!
Walking around the garden, another pair of blue butterflies attracted my attention. While they also flitted around the buckwheat, they never landed on it. When they finally did settle down, it was on plants with red flowers like the Baja Fairy Duster (Calliandra californica). The blue of these butterflies was very deep at the body and sort of iridescent. The underside was completely different with a brown zebra pattern and two or three large eye spots at the end.
My friend Yvetta has come up with two possibilities for this pair. (Why are there always two?) One is the Marine Blue (Leptotes marina) and the other is the Ceraunus Blue (Hemiargus ceraunus gyas). (Don't click on the link if seeing a beautiful butterfly stuck on a pin bothers you!) I am tending towards the Marine Blue because the striping continues all the way to the body. But what do I know?