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Close-up photo of live female Ancilla Blue (Euphilotes ancilla) ventral view

Sage Hen Rest Stop, Harney Co, June 12


Euphilotes ancilla

AKA Rocky Mountain Dotted Blue

Size: Up to 0.85 inch wingspan

Key ID features:  Small.  Male blue above with narrow dark wing borders. Female dark brown above with variable orange zigzag along trailing margin. Both sexes have checked fringe on FW. Below yellowish-gray with bold black spots, and orange edges to submarginal black spots on HW, often forming solid band.

Similar species: Best told from other Euphilotes blues by host-plant association, location and flight period.


Host plant: Eriogonum 

sphaerocephalum (rock buckwheat).

Habitat: Well-drained sites where hostplant grows, including gravelly slopes and roadsides. ​

Range: Harney County.

Season: Late May to early July

Abundance: Common


Conservation Status: Secure

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