Both sexes brown above with a broad white border and large orange submarginal spots running along the outer margin of both wings; larger than on artaxerxes (Sortbrun Blåfugl). On the male the spots on the forewing fade out toward the apex, whereas on the female they and continue toward the apex, and a very large on both wings. The ribbons are darker than the base color; contrary to artaxerxes. There is a small black discal spot on the forewing of both sexes.
Below it is very similar to artaxerxes with a broad white border and orange bands in the submarginal area. The white wedge in the center of orange band on the hindwing also doesn't reach the discal spot.
The best field mark on the underwing is that the two frontmost black spots within the orange band are positioned with number two a little closer to the apex, thus not giving the impression of the two forming a colon perpendicular to the costa.
Small and worn late summer icarus (Almindelig Blåfugl) females can sometimes be very similar to agestis, but icarus normally has at least a hint of blue near the body on the upper side and also, normally, has a black spot in the basal area of the underside forewing that both artaxerxes and agestis miss. On icarus, instead of the colon impression, the two frontal black spots and the one in the base area appear to form a curved band along the costa.
Similar species:
Life stages:
Distribution:
N Africa, S and C Europe, Turkey, Middle East toward Siberia and Amur.
Habitat:
Males both patrol and perch looking for females. Is often easy to get close to.
Behavior:
Dry and warm sandy habitat with sparse vegetation but plenty of host plants. Forest clearings, railway-terrain, costal meadows, gravel pits, abandoned terrain.
Status:
In Denmark fairly common, scattered throughout the country. In Sweden only in Skåne. Absent from Norway and Finland.
Very similar to Northern Brown Argus the two are split based on genetic differences.
Normally 2 generations (a third possible in warm years) where the first generation flies before artaxerxes and the second after.
Normally 2 generations (a third possible in warm years) where the first generation flies before artaxerxes and the second after.