France, August 2008

Male, Switzerland, spring 2008

Male, Switzerland, July 2008

Switzerland, August 2008

Male, Switzerland, July 2005

Male, Val d'Aran, July 2005

Female, Rhône Valley, May 2006

This one shows a hint of orange...

This one shows a lot of orange, but still much less than a short-tailed blue.

I once thought this species was rarer than short-tailed blue. However, I have since found it commonly in the Val d'Aran and even in my home town of Barboleuse in Switzerland in 2003. It is separable from the short-tailed blue by the lack of orange on the hindwing. The tail on the hindwing may be vestigial or apparently absent, but there is always at least a kink in the black marginal line and there seems always to be half-chequering on the margin of the hindwing upperside in the male, distinguishing this from the Osiris blue.