Euphilotes stanfordorum, Stanfords' Blue

The photograph shown here, a creative commons CC image, is of a quite similar species – Euphilotes ancilla purpura. It was taken in the Pacific Southwest Region of the United States. Euphilotes ancilla has a squarer wing and a wider wing span while its scale pattern is quite similar to Stanfords' Blue.

Stanfords' Blue has a blue dorsal upper side and a white black-dotted ventral underside with a dark yellow pattern of scales on the lower hindwing. The adult will feed on Eriogonum ovalifolium blossoms.

There are 15 species of Euphilotes – all have similar markings. Some have dark yellow scales on the ventral side, some have dark yellow scales on the dorsal side, some have an overall brown dorsal side, and some have a distinct black border on the outer edge of the dorsal wings.

When their wings are closed you would not know this butterfly was blue as the color is absent on the underside of their body. Most images of Euphilotes show them feeding with their wings closed, obscuring the blue scales.

A group of enthusiasts and nature care-takers in Ferron, Emery County, Utah, monitored the life of this butterfly and posted stunning images of the emergence of an individual butterfly.

Butterflies of America has a full set of images of Stanfords' Blue. Butterflies and Moths has information about Stanfords' Blue somewhat limited range and host plants. The Natural History Museum shows that any number of Eriogonum are host plants for Euphilotes butterflies. The USDA has a lot of information about Eriogonum, as does Calflora.