L. eros O. (=
tithonus Hbn.) (80 c, d). male very bright blue, with a metallic gloss like enamel, black margin to the forewing and black distal-marginal spots to the hindwing, these spots contrasting strongly with the pure white fringes. Female brown, sometimes with yellowish red distal-marginal spots. Underside strongly recalling
icarus, but male as well as female with distinct white median streak on the hindwing. In the higher mountains of southern Europe as far as the Alps, and in the mountain-districts of Anterior Asia. — In ab.
petrividenda Favre the hindwing beneath has no black marginal spots, but instead a white band before the margin, ab. albipicta Schultz has a white discocellular spot on the forewing above instead of the hardly visible black one. ab.
caerulescens Oberth. (80 d) are females with bright blue upperside, which occur singly and rarely in Europe, but are said to be a constant form in West China; this, however, is very improbable, and Leech says nothing about it. —
erotides Stgr. [
P. e. erotides Staudinger, 1892] (80 d), from the mountains of Southern Siberia, is a large, blue-green male-form, with broad black distal margin to the forewing, into which the deep black veins merge. —
eroides Friv. (=
anteros Frr.,
everos Gerh.)[
P. e. eroides (Frivaldszky, 1835)] is more sky-blue than greenish blue and the largest form of the species after the following one; in Eastern Europe, particularly in Russia, the Balkan Peninsula, westwards extending to Germany, where it occurs in East Prussia and Posen, though only rarely. — The males of the South Russian form
boisduvalii H.-Schiff. [
P. e. boisduvalii (Herrich-Schäffer, [1843])] (80 d) have again a different blue, being paler, purer, brighter, the outer margin of the forewing is broadly black, the black veins in the apical area of the forewing being thin but sharply marked. —
sutleja Moore [now full species
Polyommatus sutleja (Moore, 1882)], from Kashmir, is extremely close to
boisduvalii, having the same tint of blue, but its black margin is somewhat narrower and the black veins in the apical area of the forewing are not quite so sharply defined. — In
amor Stgr. [now full species
Polyommatus amor (Lang, 1884)] (80 e), from Ferghana and the Tian-shan, the blue of the upperside of the male has a violet sheen, nearly as in
icarus, and the black margin is narrower. —
napaea Gr.-Grsh. [
P. e. napaea (Grum-Grshimailo, 1891)] has likewise the same blue tint above as
icarus, but the black margin is much broader, as is also the costal area of the hindwing. From the Boro-Choro Mts. in Central Asia. —
erigone Gr.-Grsh. [now full species
Polyommatus erigone (Grum-Grshimailo, 1890)] (80 e), from the Pamir, is considerably smaller; beneath the ocelli are less prominent and the white streak of the hindwing is very distinct. Also the female bears a superficial resemblance to
icarus, whose blue colour is almost exactly the same as that of the erigone males obtained at a considerable altitude (13,000 ft.). —
pseuderos Moore [now full species
Polyommatus pseuderos Moore, 1879] extends still further south, as far as Kashmir. The distal margin with black-grey spots above; the forewing beneath without basal ocelli and the discal row of ocelli more straight. —
helena Gr.-Grsh. [now
P. e. amdoensis (Wnukowsky, 1929)]from the Sinin Mts., resembles East Russian
eroides, but the blue has already a slight tinge of violet, and the black margin is narrower. In the underside the rust-yellow submarginal spots are larger and the dark marginal spots are deeper black and more prominent. Perhaps
bilucha Moore [now full species
Polyommatus bilucha (Moore, 1884)], from Quetta, outside the Palearctic territory belongs also here — The early stages of the species do not appear to be known. The butterflies occur from June until August; they are not rare and are in the Alps among the most frequent visitors of damp places on the roads. They agree best with
argus and
argyrognomon in habits and flight. ==Range, taxonomy and subspecies==