Hemiargus ceraunus gyas

Ceraunus Blue

The Ceraunus Blue can be found much of the year, especially in the deserts where it uses Mesquite, Catclaw, and various rattlepods. It flies with - and closely resembles - Leptotes marina, but along the hindwing's upper edge, ceraunus has two dark spots that distinguish it from marina. Reakirt's Blue may also be flying with either or both of these two, and it shares the two hindwing dots with ceraunus, but it is easily recognized by the row of dark macules on the forewing. I put a side-by-side illustration below.

This is a species of blue that will open its wings occasionally for patient photographers, as will Reakirt's and the Marine Blue.

Larvae are extremely variable and can be difficult to distinguish from some other lycaenid species. I thought the one I found on Astragalus palmeri below could be a Gray Hairstreak. However, we know that ceraunus has a yellow form, and that it uses this species of Astragalus, and I've seen adults in the immediate vicinity in the past. One way to be sure is to take it home and rear it to adulthood, but I wasn't prepared to do that (and can live with the slight uncertainty).

Hemiargus ceraunus gyas - 'Edward's' Ceraunus Blue
Ventral of 'Edward's' subspecies of the Ceraunus Blue. Yaqui Well, Anza-Borrego Desert State Park, October 11, 2005.
Hemiargus ceraunus gyas - 'Edward's' Ceraunus Blue
Male Ceraunus Blue. Plum Canyon, Anza-Borrego, October 10, 2005.
Hemiargus ceraunus gyas - 'Edward's' Ceraunus Blue
Female Hemiargus ceraunus gyas, Boyce Thompson Arboretum in Arizona, September 25, 2007.
Hemiargus ceraunus gyas - 'Edward's' Ceraunus Blue
Another Hemiargus ceraunus gyas, this from Cactus Spring Trail in Riverside County, May 26, 2012.
Hemiargus ceraunus gyas - 'Edward's' Ceraunus Blue
Another male Ceraunus Blue. Same individual as above.
Comparing Hemiargus ceraunus gyas, Hemiargus isola arce, and Leptotes marina
From left to right: Leptotes marina (Marine Blue); Hemiargus ceraunus gyas (Ceraunus Blue); and Hemiargus isola alce (Reakirt's Blue). Marina lacks the two hindwing spots on the upper margin of the other two, and only Reakirt's has the row of black dots that are a prominent feature of the forewing.
Larva of Hemiargus ceraunus gyas - 'Edward's' Ceraunus Blue butterfly caterpillar
The Ceraunus Blue uses Astragalus palmeri as one of its hosts. This yellow form larva - it has many forms - was at Cactus Spring Trail near the so-called Dolomite Mine on June 3, 2017.

©Dennis Walker