Neither male nor female of this species exhibits any trace of blue. The upper surface, shown in fig. 13 of Plate VI, is coloured with a warm brown, and all four wings have a row of orange spots near the hind margin. The fore wings have also a central black spot. The under surface, drawn on the same plate (fig. 14), is bluish grey, with a border of orange spots on each hind margin as on the other side. There are also numerous black spots in light rings, the arrangement of which will be seen in the figure. Some species of butterflies and moths are so variable in their colouring and markings that varieties have often been mistaken for distinct species; and, in other cases, distinct species are sometimes so similar in character that they are looked upon as identical. A butterfly that closely resembles the normal Brown Argus in many points, and named _Artaxerxes_, has often been described as a distinct species, but is now, I believe, recognised by most entomologists as a constant variety of the present species. It differs from the normal type in having a _white_ instead of a _black_ spot in the centre of the fore wings, and the border of orange spots is often very indistinct. On the under side, too, instead of black spots in white rings, it has white spots, with little or no trace of a black centre. The ordinary Brown Argus is a southerner, and is particularly abundant on the chalk downs of the south coast and the Isle of Wight, but _Artaxerxes_ is to be found only in Scotland and the north of England; and it is interesting to note that, between these northern and southern districts, intermediate varieties are to be met with. Again, _Astrarche_ is a double-brooded butterfly, appearing on the wing in May and August; while _Artaxerxes_ is single brooded, flying at midsummer. This fact has lent support to the opinion that the two are distinct species; but it must be remembered that several insects that are single brooded in one country are double brooded in a warmer climate. The caterpillar of _Astrarche_ feeds on the hemlock stork's-bill (_Erodium cicutarium_). It is of a pale yellow colour, with a brownish line on the back; and is full fed in April and July. _The Common Blue_ (_Lycaena Icarus_) Although this pretty little butterfly is so common that it is almost sure to be known to all who take any interest in insect life, yet it is important to observe it carefully, since it is an easy matter to confound it with other species of the same genus. The upper surfaces of the two sexes are very different, that of the male (Plate VI, fig. 15) being a beautiful lilac blue; and that of the female (Plate VI, fig. 16) a dark brown, powdered with blue at the bases of the wings, and having _generally_ a border of orange spots, more or less defined, on the hind margins of all wings. [Illustration: FIG. 89.--THE COMMON BLUE--UNDER SIDE.]