As I am finding out, when trying to identify the small blue butterflies, you require a photo of the underside of the wings and a good reference book. The Balkan zephyr blue has a wingspan of 27 to 32mm. The upper wings of the male are an inky dark blue with a white outer border. Inside this is a thin black line followed by black spots on the hind wings. The underside of the wings is a silvery grey, with black spots bordered with white and orange spots on the edge of the wing. The female upper wings are brown with orange spots.