Euphilotes pallescens elvirae

Elvira's Pallid Blue

This is a rarely-seen blue of the deserts. In southern California, these may be found - if you're fortunate - in patches of Eriogonum plumatella in toasty habitats few are visiting when flights begin in late July/August, and continue into September and perhaps October. The type locality is "3.5 miles southwest of Pearblossom," and there are records from various washes in that area. I've tried a few locations in the Pearblossom area and found plenty of plumatella, but not this distinctive blue. This year (2019), however, I received a good tip about a location within Joshua Tree National Park, and was led to a colony of this butterfly in a place I would never have found on my own. I visited twice in three days and was able to experience this blue for hours. It was just about the only butterfly on the wing other than various white skippers present because of the abundant Apricot Mallow. Males of elvirae weren't opening their wings; females sometimes were. In two visits, I got lots of ventral shots, just one female with wings open, and no male dorsal photos. All-in-all, it was a special experience, as I've wanted to see this butterfly for many years.

Euphilotes pallescens elvirae - Elvira's Pallid Blue butterfly
This appeared to be a female Euphilotes pallescens elvirae ovipositing on the host buckwheat, Eriogonum plumatella, in Joshua Tree National Park. August 27, 2019.
Euphilotes pallescens elvirae - Elvira's Pallid Blue butterfly
Another pallid blue, probably a female. August 29, 2019.
Euphilotes pallescens elvirae - Elvira's Pallid Blue butterfly
Mattoni described the ground color of the underside of females as "cream white", and males as "light cream gray". The females also have larger black macules than those of males on the underside. With this mating pair, the difference is obvious. August 29, 2019.
Euphilotes pallescens elvirae - Elvira's Pallid Blue butterfly
Females are brown on the dorsal side, males blue. Opler (Western Butterflies, p.241) says males often lack the orange aurora seen here on the female. August 27, 2019.
Euphilotes pallescens elvirae - Elvira's Pallid Blue butterfly
One last female, highlighting the orange aurora and black bands. I had wondered how distinctive these would be to the naked eye in the field compared to other blues. To my eye, the contrast of the black markings against the white ground color and the continuous orange aurora really stood out. August 27, 2019.
original description of Euphilotes pallescens elvirae
Rudi H. Mattoni's original description of what was initially Philotes rita elvirae, from his article "Distribution and Pattern of Variation in Philotes rita," in the Journal of Research on the Lepidoptera in 1965.

©Dennis Walker