(Verity, 1927)
Description:
This is a butterfly of warm, dry grassland and dry, coniferous forests on calcareous soils. In Switzerland, it is only found where its food plant Astragalus exscapus grows. In Italy, it also lays its eggs on A. centralpinus, a milk-vetch that does not occur in Switzerland.
The caterpillars hibernate when they are half-grown, and resume feeding in spring, choosing young shoots near to the ground. They are also found keeping company with ants.
This blue is single-brooded.
Habitat:
Dry calcareous grasslands
Similar species:
Plebeius argus
Plebeius idas
Polyommatus escheri