Eumedonia eumedon, the geranium argus, is a butterfly of the family Lycaenidae.

Beneath brown, with red-yellow distal band, which is either continuous, or separated into spots, and either restricted to the hindwing or continued on to the forewing, or may be entirely absent; the base of the wings beneath dusted with very glossy metallic scaling; ocelli similarly arranged as in astrarche typical specimens bearing also a distinct white streak from the central spot of hindwing to outer margin.

The butterflies occur from May till July, in the high Alps until August; they fly rather slowly and clumsily, nearly always about the flowers of Geranium, also passing the night asleep in the blossoms of the plants.

During flight they move the wings very regularly up and down and often remain fluttering in the air in front of a flower before settling on it.

The sexes are of equal frequency and appear to leave but unwillingly their flight-places, where one often meets with pairs in copula.