Identifying features
Wingspan: 26-33 mm. The male's upperside is dark violet-blue with a narrow black border and rather prominent, thin dark wing veins.
Similar species
When viewed from above, the species may be confused with several other blue butterflies. However, Mazarine blue is distinguished by its dark blue ground colour and the thin, dark veins that extend outwards – and often merge with the scales. Silver-studded blue and Idas blue exhibit a sky blue ground colour, while common blue has a very narrow, dark border.
Distribution
The Mazarine blue was once very common in Jutland, but in just 20 years it has disappeared from nearly 9/10 of its sites. On Samsø, the species still has several good sites.
Biology
The species' larvae primarily feed on red clover, but certain other clover species are also known as host plants in Denmark.