Osiris Blue
Cupido osiris
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Male on sainfoin (the larval foodplant), Switzerland, June 2005

The same male

Male, June 2006, Switzerland

This picture was taken two days after the above one, at the same site. I think it is the same butterfly...

Typical brown female, June 2005

Female, June 2006

Male on sainfoin

Underside (this is a female, but the male is similar)

Exceptionally blue female

The same female, Switzerland, June 2005

Another shot of the same butterfly

Osiris blues are relatively uncommon butterflies, found from West Switzerland through to North Spain and North Italy, and also more widely further east. The male is a bright violet-blue while the female is normally brown, and both sexes are considerably larger than their nearest relatives, the little blues.

The last female above was the first Osiris blue I had ever seen and posed me some problems of identification because she is so blue. Although I was convinced she was Osiris, not all my friends agreed and I put this page on hold. Nearly a week after seeing her I found a male (or perhaps two or even three males - I am not sure how many different insects I saw because they were very twitchy) in the same place. I almost always saw males stop on sainfoin, the larval foodplant, though the aberrant female of a week before freely stopped on any plants.

Since then I have found more sites and become more familiar with the butterfly. Males are easily identifiable in flight, the combination of rather dull, violet blue with white undersides and a powerful, restless movement being characteristic. They almost invariably show an interest in sainfoin and very rarely even consider settling elsewhere. I have occasionally seen them settle on grass flowers in order to sun themselves.

The books make one think this is a small butterfly but it does not seem small at all in real life. It can certainly hold its own against a common blue.