Green-underside blue

Glaucopsyche alexis aeruginosa

A small blue butterfly with a wingspan of 27-36 mm. As with many blues, males are blue while females are brownish; the undersides of the hindwings are shiny green, hence the name. The green-underside lives in many different types of habitats, particularly in the western part of the country, in coastal farmland, riversides, scrub, woodland, damp meadows, forest clearings, and mountain pastures. Host plants consist of many species of legumes, such as thorny-broom (Calicotome villosa), crown-vetch (Coronilla varia), Spanish broom (Spartium junceum), meadow vetchling (Lathyrus pratensis), brooms (Cytisus spp.), medicks (Medicago spp.), clovers (Trifolium spp.), vetches (Vicia spp.), and milk-vetches (Astragalus spp.). It flies April through early July.

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