Very similar to the Common Blue (P. icarus), usually slightly smaller. The male upperside is bright blue with a violet tinge, and there is a narrow, but

strong and even, black border on both wings. The underside is very similar to icarus although the key identifier is the absence of a unf cell spot which icarus nearly always has, even if sometimes very small. It is not always easy to see this as it is near the base of the wing, especially if the forewing is tucked down and the cell spot (or lack of it) is not visible. The unh marginal orange lunules tend to be brighter and more elongated with pointed ends, and the black “dashes” inside the white marginal areas tend to be more centrally located within these white areas, compared to icarus where they are usually close to the orange, if not actually touching it. The underside ground colour is pale brown in the female and greyish in the first brood males, although second brood males seem usually to have a brownish ground colour.

First brood females have a good degree of blue scales, whereas second brood females are more classically brown with orange lunules. First brood females could be confused with icarus - see the icarus page for possible means of differentiating. It is an early emerger, usually being on the wing in April in the south of France.

This species is referred to as Agrodiaetus thersites in T&L, but now seems to be classified as a member of the Polyommatus family.

observations

this male shows the strong deep blue, deeper than icarus, with the clear clean black border of constant width.

a first brood female, with rather limited blue scaling possibly as a result of ageing (they emerge early in Var).

a male of the first brood, helpfully showing a raised forewing to make it clear that there is no cell spot.

a male underside, quite a cold grey (even the male underside can be quite brownish, as shown on this page), and with some slight aberration of the unf black spots.

a male, puddling at an altitude of 2100m, about the upper limit of its altitude range.

a rather worn female underside. As with 10014, the forewing is raised, showing the absence of a cell spot.

a fairly typical female underside ground colour, with a heavily spotted unf and elongated unh lunules.

a rather pale female, perhaps slightly due to wear, with large orange unh lunules.