The silver-studded blue is a butterfly in the family Lycaenidae. It has bright blue wings rimmed in black with white edges and silver spots on its hindwings, lending it the name of the silver-studded blue. P. argus can be found across Europe and east across the Palearctic, but it is most often studied in the United Kingdom where the species has experienced a severe decline in population due to habitat loss and fragmentation.

Lycaenidae is the second-largest family of butterflies, with over 6,000 species worldwide, whose members are also called gossamer-winged butterflies. They constitute about 30% of the known butterfly species.