Butterflies and Moths Part 25

It is probable that the caterpillar was a hybernator, seeking its winter shelter while still very young; and it was full fed in June.

Its colour was green, with a darker stripe of the same colour on the back; and the chrysalis was attached by a.n.a.l hooks and a cord round the body.

_The Small Copper_ (_Polyommatus Phlaeas_)

The only other British member of the genus _Polyommatus_--the Small Copper--is one of the commonest of our b.u.t.terflies. It may be found in nearly all parts of the British Isles from April to September, more particularly in April, June, _and_ August, for it is apparently triple brooded.

This brilliant and lively little insect is shown on Plate VI (fig. 9), and, being so very familiar, needs no description.

The caterpillar feeds on different species of dock--the broad-leaved dock (_Rumex obtusifolius_), the fiddle dock (_R. pulcher_), the sorrel (_R. acetosa_), and the sheep sorrel (_R. acetosella_); also on the ragwort (_Senecio Jacobaea_). It is full fed about three weeks after hatching, and then changes to a small and stout chrysalis, of a pale brown colour, on the leaf of its food plant.

The caterpillar itself is green, with a reddish line on the back and on each side; and it glides over the surface of the leaves something after the manner of a slug, without exhibiting any very apparent motion of its short legs and claspers.

_The Tailed Blue_ (_Lycaena Baetica_)

We now come to a genus containing no less than ten species of beautiful little b.u.t.terflies, known commonly as the 'Blues;' but one of them exhibits no trace of the colour so characteristic of the group, although it resembles the others in structure and habits.

Our first example is the Tailed Blue, known also as the Pea-pod Argus.

The upper side of this insect (Plate VI, fig. 10) is of a dull smoke colour, exhibiting purple-blue reflections, which are, in the female, confined to distinct blotches on the bases of the wings, but in the male are less noticeable, and extend over the whole surface. The hind margin of the hind wings has a row of spots, more or less distinct, and much more prominent in the female than in the male. The under side is beautifully marked with bands of fawn and grey, and with two spots of brilliant metallic green in the a.n.a.l angle of the hind wings.

[Ill.u.s.tration: FIG. 87.--THE TAILED BLUE--UNDER SIDE.]

This b.u.t.terfly abounds in the countries of South Europe, where the caterpillar feeds on the pods of certain leguminous plants; but only a few stragglers have been taken in England, so that its reputation as a true Britisher is very uncertain. It is highly probable that the two or three specimens caught on our south coast were blown over from the Continent, and that the insect has never bred on this side of the Channel.

_The Silver-studded Blue_ (_Lycaena aegon_)

The upper surface of the male (Plate VI, fig. 11) of this species is purple blue, with a black border on the hind margins of all wings. The female (fig. 12 of the same plate) is of a very dark smoky-brown colour, often with a bluish tinge, and has generally a row of orange spots near the hind margin of the hind wings.

The under side of both s.e.xes is similar, and is ill.u.s.trated in the accompanying woodcut. The ground colour is bluish grey, and is marked with a number of black spots surrounded by light rings. Along the hind margin of the hind wings is a row of orange spots, each bordered with black on the inner side, and with a silvery blue on the outer.

[Ill.u.s.tration: FIG. 88. THE SILVER-STUDDED BLUE--UNDER SIDE.]

This insect appears in July, and is common in many dry, sandy, or chalky spots in various parts of England, and also in a few localities in Scotland and Ireland. It has been reported as abundant at Darlington and in certain localities in Lancas.h.i.+re, but its head quarters are undoubtedly the chalk downs and dry gravelly banks of the southern counties.

The caterpillar feeds on the bird's-foot (_Ornithopus perpusillus_), and is full grown towards the end of June. Its colour is yellow or grey, with a brown dorsal stripe, a white line on each side, and pale oblique lines near the former. About the end of June it changes to a dull green chrysalis, with projecting wing cases.

_The Brown Argus_ (_Lycaena Astrarche_)

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 b.u.t.terflies 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 b.u.t.terfly 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 b.u.t.terfly, 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 b.u.t.terfly 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 s.e.xes 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.

[Ill.u.s.tration: FIG. 89.--THE COMMON BLUE--UNDER SIDE.]

The under side, shown in the accompanying woodcut, is ashy brown; warm in the female, but paler in the male. The hind wings, and sometimes all four, are bordered with orange spots; and this species may be distinguished from _Astrarche_ by the presence of two black spots, in white rings, near the base of the fore wings.

There will be no need to name localities for this insect, as it is abundant everywhere, frequenting meadows, heaths, and all waste places.

It is double brooded, and is on the wing continuously from May to September, the first brood enduring from May to July, and the second from July to the end of the warm weather.

The caterpillar is green, with a dorsal line of a darker tint, and a row of white spots on each side. It feeds on clover (_Trifolium pratense_ and _T. repens_), bird's-foot (_Ornithopus perpusillus_), bird's-foot trefoil (_Lotus corniculatus_), and the rest-harrow (_Ononis spinosa_).

The chrysalis is short and rounded, of a dull green colour, tinged with brown on the under surface.

_The Clifden Blue_ (_Lycaena Bellargus_)

Our coloured representations of this beautiful blue (Plate VI, figs. 17 and 18) show that here also there is a great difference between the male and female. The former is a most lovely and brilliant sky blue, bordered by a fine black line; and the latter is a dull dark brown, with a more or less distinct border of orange spots, and the bases of the wings are powdered with scales of a tint corresponding with those of the male. In both s.e.xes the fringe is very distinctly barred with dark brown.

[Ill.u.s.tration: FIG. 90.--THE CLIFDEN BLUE--UNDER SIDE.]

The under side (fig. 90) is similar in both s.e.xes--greyish brown, with a border of reddish spots, and a number of black spots in white rings, the arrangement of which is here represented.

The b.u.t.terfly frequents chalky downs, chiefly in the south of England, and seems to be unknown in Scotland and Ireland. The Isle of Wight, and the chalky downs and banks of Suss.e.x, Surrey, and Kent, are its favourite localities; and even in these it is generally very local, sometimes swarming on a gra.s.sy bank of no great extent, when the surrounding neighbourhood, though apparently equally suitable to its requirements, does not harbour a single specimen. It is on the wing in May and June, and again in August.

The caterpillar is green, with two rows of yellow streaks on the back, and a yellow stripe on each side. It feeds on the Dutch clover (_Trifolium repens_), horse-shoe vetch (_Hippocrepis comosa_), and various other leguminous plants.

_The Chalk-Hill Blue_ (_Lycaena Corydon_)

The male of this species (Plate VII, fig. 1) is readily to be distinguished from all other members of the genus by its pale glossy blue, but the female (fig. 2 of Plate VII) so closely resembles that of _Bellargus_ that it is often a somewhat difficult matter to discriminate between them. The following, however, are a few points worthy of observation: The upper side of the female _Corydon_ has the bases of the wings more or less sprinkled with the pale silky blue that characterises the male; and the black bars of the fringe are _usually_ broader in _Corydon_ than in _Bellargus_. The black-centred spots of the under side are also usually more conspicuous in the former species than in the latter.

[Ill.u.s.tration: FIG. 91.--THE CHALK HILL BLUE--UNDER SIDE.]

The difficulty of identification is increased by the fact that both these b.u.t.terflies frequent similar localities, and are often on the wing at the same time; but although _Corydon_ is certainly a frequenter of chalky districts, yet it is often found plentifully in districts far removed from the chalk, notably at Arnside in Lancas.h.i.+re, and in Epping Forest.

The b.u.t.terfly is out in June and July. The caterpillar is green, with two rows of short yellow streaks on the back, and a yellow stripe on each side. It feeds on the purple and Dutch clovers (_Trifolium pratense_ and _T. repens_), bird's-foot trefoil (_Lotus corniculatus_), horse-shoe vetch (_Hippocrepis comosa_), and lady's fingers (_Anthyllis vulneraria_).