THE PEARL-BORDERED FRITILLARY. (Argynnis Euphrosyne.)
(Plate X. fig. 4.)
This very common insect is considerably smaller than any of the preceding species, though small specimens of the last sometimes do not much exceed it in size. The upper surface is lively orange-brown, with black markings. Beneath, the hind wing is mapped out with black lines into various irregular spaces, all of which are filled with tints of dull yellow, ochreous, or reddish orange; excepting a row of silver spots on the border, one silver spot in the centre of the wing, and one triangular one close to the root of the wing.
The caterpillar is black, with white lines; and the pro-legs red. It feeds on various species of viola.
The butterfly appears first in May, and there is another brood in autumn, about August. It frequents woods and hedgerows, being met with most profusely in the south; but its range is extended into Scotland. In Ireland I believe it is unknown.
THE SMALL PEARL-BORDERED FRITILLARY. (Argynnis Selene.)
(Plate XI. fig. 1.)
This butterfly, which is very nearly related to the last, often so closely resembles it in the marking of the upper surface, that even practised eyes are sometimes at a loss to distinguish the two, without a reference to the under side; for on this side do the real distinctive marks lie, and chiefly on the hind wing. In addition to the silver border and central spots of Euphrosyne, this species has several other silvery or pearly patches distributed over the hind wing; and the reddish-orange colour adjoining the silver border in Euphrosyne is exchanged for dark chestnut-brown in Selene. In average size the two insects differ very slightly, though the name of this expresses an inferior size.
The caterpillar much resembles that of the last, and feeds on violet-leaves.
The chrysalis is greyish.
The butterfly is double-brooded, appearing first in May and again in August. It is not so common an insect as Euphrosyne, but is met with in similar situations, and has a range nearly co-extensive with that of the latter.
THE GLANVILLE FRITILLARY. (Melitæa Cinxia.)
(Plate XI. fig. 2.)
Though usually rather abundant where it occurs at all, this insect is one of the most local of all our butterflies, and I can only find recorded about a dozen places for it in the country. Of these, the Isle of Wight is the great metropolis of the insect, and there, in many places round the coast, numerous colonies have been established.
This butterfly is distinguished from the next (M. Athalia), which it very much resembles, principally by the characters on the under surface.
The hind wing (beneath) is covered with alternate bands of bright straw-colour and orange-brown, divided by black lines; and possesses in the marginal straw-coloured band a row of clear BLACK SPOTS. Another row of black spots crosses the centre of the wing. It will also be observed that the hind wings have on their upper surface a row of black spots parallel with, and not far from, the margin. The colouring of the upper side is orange-brown with black markings.
The caterpillar, which feeds on the narrow-leaved plantain, is thorny and black, with reddish head and legs. The chrysalis is brownish, marked with fulvous tint. A highly interesting account of the habits and history of this butterfly in all its stages has been sketched from the life by the Rev. J. F. Dawson (who has made an intimate acquaintance with a colony of the insect at Sandown, Isle of Wight), and will be found in the Zoologist, p. 1271.
The butterfly first appears about the first or second week in May, and thence continues till about the middle of June, seldom enduring till July. It is to be looked for in rough, broken ground, such as the Isle of Wight landslips, where plenty of the narrow-leaved plantain grows.
Other localities for the Glanville Fritillary are, Folkestone below West-Cliff (abundant); round Dover; Birchwood; Dartford, Kent; Stapleford, near Cambridge; Yorkshire; Lincolnshire; Wiltshire; Peterboro', Stowmarket; and in Scotland, at Falkland in Fifeshire.
THE PEARL-BORDERED LIKENESS FRITILLARY. (Melitæa Athalia.)
(Plate XI. fig. 3.)
This is another very local butterfly, though rather more widely and generally distributed than the last, which, as before stated, it greatly resembles in appearance, especially on the upper side.
It may be characterised negatively as not having the rows of black spots found on both surfaces of Cinxia, though its colouring is very similar—fulvous (or orange-brown) and black above; straw-coloured, fulvous, and black beneath.
The caterpillar is black, with rust-coloured spines; and feeds on various species of plantain.
The butterfly is out from May to July, and is met with (if at all) on heaths, clearings in woods, &c. Localities, in some of which it is very plentiful, are, Caen Wood; Coombe Wood; Epping; Halton, Bucks; Bedford; Aspley Wood, Beds; Plymouth, Teignmouth, Stowmarket, Dartmoor, Devonshire; Oxford; Wiltshire; Colchester; St. Osyth; Tenterden; Faversham; Deal; Canterbury. Very rare in north of England.
THE GREASY OR MARSH FRITILLARY. (Melitæa Artemis.)
(Plate XI. fig. 4.)
The black markings on the upper side of this butterfly closely approach those of the last two species, but the interstices, instead of being filled up with a uniform fulvous tint, as in those, are "coloured in" with several distinct shades, some with pale tawny yellow, others with deep orange brown. This latter tint forms a band parallel to the outer margin of each wing, the band on the front wings having a row of pale spots in it; that on the hind wings a row of black spots. Beneath, the upper wing has an appearance of the markings having been "smudged" together, and a shining surface, as if it had been greased, whence the common name of the insect; the hinder wings are like those of the two last, yellowish, banded with brownish orange, the outer band of which bears a series of black spots each surrounded by a pale yellowish ring.
The front edge of the front wing is slightly concave in its outline, about the middle, whereas it is convex in Cinxia and Athalia.
The caterpillar is black, with reddish brown legs. It is gregarious, feeding under protection of a web upon the leaves of plantain, devils-bit scabious, and some other plants.
The chrysalis is drabbish, with darker spots, and is said to suspend itself by the tail from the top of a tent-like structure made of blades of grass spun together at the top.
The butterfly appears in June (sometimes a little earlier or later), and frequents marshy meadows, moist woods, &c., but is a very local insect, abounding most in the south. The specimens, however, that I have seen from the north, are much larger, brighter, and more distinctly marked than the "southerners." The nearest localities to London are, Hornsey, and Copthall Wood at the top of Muswell Hill; West Wickham Wood, and High-Beech (Epping). It is also found near Brighton (plentifully); Carlisle; Durham; Burton-on-Trent; York; Haverfordwest, S. W.; Cardiff, S. W.; Weston-super-Mare; Bristol; and a great number of other places distributed throughout the country. In Ireland at Ardrahan, co. Galway. Rare in Scotland.
THE DUKE OF BURGUNDY FRITILLARY. (Nemeobius Lucina.)
(Plate XI. fig. 5.)
Though this little insect bears the name of Fritillary, at the end of its lengthy and important title, it really belongs to a family widely differing from that of any of the true Fritillaries previously described, and it only shared their name on account of its similarity in colour and markings.
The caterpillar (Plate I. fig. 8), instead of being long and thorny like those of the true Fritillaries, is short, thick, and wood-louse shaped. Its colour is reddish brown, with tufts of hair of the same colour. It feeds on the primrose.
The chrysalis differs from that of the true Fritillaries as much as the caterpillar does, being of the form, and suspended in the manner, shown at fig. 25, Plate I.
The butterfly is chequered on the upper surface with tawny, and dark brown or black. It appears in May and June, and again in August, being found in woods, principally in the south, and its range is often confined to a small spot hardly fifty yards in diameter, within which it may be quite plentiful. The following are among its recorded localities:—Carlisle; Lake District; West Yorkshire; Roche Abbey, Yorkshire; Peterborough; Stowmarket; Pembury; Barnwell Wold, Northants; Oxford; Blandford; Worcester; Gloucestershire; Bedfordshire; Epping; Coombe Wood; Darenth Wood; Boxhill; Dorking; Brighton; Lewes; Worthing; Lyndhurst; Teignmouth.
The males of all the members of the family to which this butterfly belongs, and of which this is the sole European representative—the Erycinidæ—have only four legs adapted for walking, whilst the females have six.
THE BROWN HAIR-STREAK. (Thecla Betulæ.)
(Plate XII. fig. 1, Male; 1 a, Female.)
The genus to which this butterfly belongs, contains five British species, elegant and interesting insects, though not gaily tinted. They are most obviously distinguished from other small butterflies by the tail-like projection on the lower edge of their hind wings (though one of their number, T. Rubi, has this very slightly developed). From each other they are best distinguished by the characters on their under surface, where they all bear a more or less distinct hair-like streak, whence their common name—Hair-streak.
The Brown Hair-streak is the largest of the genus, measuring sometimes an inch and two-thirds in expanse. The two sexes differ considerably on the upper surface, the male being of a deep brown colour, slightly paler near the middle of the front wing, while the female possesses on the front wing a large patch of clear orange. Both sexes have several orange marks upon the lower angles of the hind wings. Beneath, the general colour is tawny orange with duller bands, and marked with one white line on the front wing, and two parallel white lines on the hind wings.
The caterpillar is green, marked obliquely with white; it feeds on the birch and also on the sloe.
The butterfly appears in August, continuing into September. It is generally distributed through the south, but is by no means an abundant insect. Mr. Stainton observes that it has a habit of "flitting along in hedges just in advance of the collector;" but it is also found in oak woods in company with the Purple Hair-streak.
Forty were taken in a season in woods near Henfield, Sussex. Other localities are, Underbarrow Moss, Westmoreland; North Lancashire, common in some parts; Preston; Valley of the Dovey, Montgomeryshire; Cardiff, S. W.; Barnwell Wold; Peterborough; Colchester; Epping; Darenth Wood; Coombe Wood; Brighton; Tenterden; Winchester; Woolmer Forest, Hants; Plymouth; Dartmoor; Wallingford, Berks; Ipswich; Dorsetshire; Norfolk; Wiltshire; Monks Wood, Cambridgeshire.
THE BLACK HAIR-STREAK. (Thecla Pruni.)
(Plate XII. fig. 2.)
The upper side is very dark brown, sometimes almost black, and bearing near the hinder edge of the hind wings a few orange spots. This character will at once distinguish this from the next species (W. Album). On the under side of the hind wing is a broad band of orange, having a row of black spots on its inner edge.
The caterpillar is green, with four rows of yellow spots. It feeds on the sloe.
The butterfly comes out about the end of June or in July. It is generally a very rare insect, but is occasionally taken in great plenty in certain spots. The Rev. W. Bree, writing to the Zoologist from the neighbourhood of Polebrook, North Hants, says, "Thecla Pruni is very uncertain in its appearance. In 1837 it literally swarmed in Barnwell and Ashton Wolds; I do not scruple to say that it would have been possible to capture some hundreds of them, had one been so disposed; for the last few years it has appeared very sparingly indeed." It has also been found in the following localities:—Overton Wood; Brington, Huntingdonshire; and Monks Wood, Cambridgeshire.
THE WHITE LETTER HAIR-STREAK. (Thecla W. Album.)
(Plate XII. fig. 3.)
This is very much like the last in appearance, and has often been mistaken for it by inexperienced eyes. The points of difference are—on the upper side, the absence of the orange band at the hinder edge of the hind wings, and the presence of a bluish grey circumflex line at the inner angle; here also is sometimes a small orange dot;—beneath, the orange band forms a series of arches, bounded on the edge nearest the root of the wing by a clear black line instead of the rounded black spots seen at this part in Pruni.
The caterpillar, which feeds on the elm, is wood-louse shaped; pea-green, barred with yellow; head black. May be beaten off elm trees in May.
The butterfly appears in July, and is found in various situations, sometimes flying high up round elm trees, sometimes descending to bramble hedges, or fluttering about in weedy fields a foot or two from the ground. It was formerly a much rarer insect than at present, and now its appearance in any given locality is a matter of much uncertainty. Mr. J. F. Stephens writes as follows to the Zoologist:—
"For eighteen years I possessed four bleached specimens only of Thecla W. Album, having vainly endeavoured to procure others, when, in 1827, as elsewhere recorded, I saw the insect at Ripley, not by dozens only, but by scores of thousands! and although I frequented the same locality for thirteen years subsequently, sometimes in the season for a month together, I have not since seen a single specimen there; but in 1833 I caught one specimen at Madingley Wood, near Cambridge."
Other localities:—Near Sheffield; Roche Abbey; York; Peterborough; near Doncaster; Polebrook, Northants; Allesley, Warwickshire; Brington, Huntingdonshire; Yaxley and Monks Wood, Cambridgeshire; Needwood Forest, Staffordshire; Wolverston, near Ipswich; Chatham; Southgate, Middlesex; West Wickham Wood; Epping; Bristol.
THE PURPLE HAIR-STREAK.(Thecla Quercus.)
(Plate XII. fig. 4, Male; 4 a, Female.)
At once the commonest and the handsomest of the Hair-streaks, being found in almost every part of England where there is an oak wood, and looking like a small Purple Emperor, with its rich gloss of the imperial colour.
The male has all the wings, in certain lights, of a dark brown colour, but with a change of position they become illuminated with a deep rich purple tint, extending over the whole surface excepting a narrow border, which then appears black. The female has the purple much more vivid, but confined to a small patch extending from the root to the centre of the front wing. Beneath, the wings are shaded with greyish tints, crossed by a white line on each wing, and having two orange spots at the inner corner of the hind wing.
The caterpillar (Plate I. fig. 9), which feeds on the oak, is reddish brown, marked with black.
The chrysalis, which is sometimes attached to the leaves of the oak, and at others is found under the surface of the earth at the foot of the tree, is a brownish object, of the lumpy shape shown in Plate I. fig. 28 (a form shared by the chrysalides of all the Hair-streaks).
The butterfly is seen in July and August, flitting about in sportive groups round oak trees, and occasionally descending within reach of the net. It also affects other trees besides oaks, some thirty or forty at a time having been seen gambolling about one lime tree. It being so generally distributed, it will be needless to particularize its localities.
THE GREEN HAIR-STREAK. (Thecla Rubi.)
(Plate XII. fig. 5.)
This pretty little species is at once known from all other English butterflies by the rich bright green colour that overspreads its under surface. Above, the wings are deep, warm brown.
The caterpillar is green, spotted and striped with white, and feeds on the bramble; also on the broom, and other plants of the same order.
The butterfly appears first in May and June, and again in August, it being double-brooded. It is found flying about rough brambly hedges, and often settles on the outer leaves of low trees about a dozen feet from the ground. It seems to occur generally throughout the country, and extends into the southern parts of Scotland. It has been found in many localities close to London.
THE SMALL COPPER BUTTERFLY. (Chrysophanus Phlæas.)
(Plate XIII. fig. 1.)
We now arrive at a genus characterized by the splendid golden or burnished coppery lustre and tint of their wings; of which, however, the present little species is the only one that remains to us, should the "Large Copper" be really (as it is feared) extinct.
This little, but lively representative of the genus, is one of our commonest and most widely distributed butterflies, flashing about in the sunshine, joining in a dance with the no less lively blues, or settling on the lilac flowers of the scabious, &c., whose soft tones set off to the best advantage the metallic effulgence of this little gem.
The caterpillar feeds on sorrel leaves; is green, with three red stripes.
The chrysalis and caterpillar both resemble in shape those of the Hair-streaks.
The butterfly is supposed to be triple-brooded, coming out in April, June, and August; and is so common, that no localities need be given.
THE LARGE COPPER BUTTERFLY. (Chrysophanus Dispar.)
(Plate XIII. fig. 2.)
A few years ago, this was the pride of British entomology, for we were supposed to have the insect entirely to ourselves, it being unknown on the Continent, whilst it literally swarmed in some of the fens of Cambridgeshire and Huntingdonshire. Then, from some cause, never satisfactorily explained, it almost suddenly disappeared, and, there is reason to fear, has become quite extinct in this country. Still, hopes are entertained that it may be surviving in some unexplored districts, and that it will again "turn up."
As comparatively very few persons have ever seen this splendid creature on the wing, the following communication from one who has, quoted from the Intelligencer, will be of interest to those who have not read it in that periodical. It is from the pen of Mr. E. C. F. Jenkins, of Sleaford, Lincolnshire. He writes: "I proceed to give you some account of my own acquaintance with that most beautiful insect, which, some thirty years ago, was so abundant in the unreclaimed fens about Whittlesea Mere, that I never expected to hear of its utter extermination. Its brilliant appearance on the wing in the sunshine I shall never forget, and to watch it sitting on the flower of the Eupatorium cannabinum and show the under sides of its wings, was something ever to be remembered. I once took sixteen in about half an hour on one particular spot, where the above-mentioned plant was very plentiful; but unless the sun was very bright they were very difficult to find. In those days the larva was unknown, and I attribute the disappearance of the butterfly to the discovery of the larva, to the unceasing attacks of collectors, and to the burning of the surface-growth of the fens, which is done in dry weather when they are to be reclaimed."
The two sexes of this butterfly differ very remarkably in the appearance of the upper surface. This, in the male, is of an effulgent coppery colour, narrowly bordered with black, and having a black mark in the centre of each wing. The female is larger, has a redder tinge, with a row of black spots on the front wings, and the hind wings nearly covered with black, excepting a band of coppery red near the margin, extending also more or less distinctly along the courses of the veins. Underneath, both sexes are nearly alike, the hind wing of a general light blue tint, with a red band near the margin, and spotted with black.
The caterpillar is green, darker on the back, and paler at the sides, it feeds on the water dock.
The butterfly used to be found in July and August, being formerly especially abundant about Yaxley and Whittlesea Mere, and has been taken also at Benacre, Suffolk; and Bardolph Fen, Norfolk.
Various reports of its capture, during the last two or three years, have been published; but they all seem to require confirmation.
This butterfly is now generally considered to be a large local variety of the continental one called Hippothoë, with which it closely agrees in its markings.
THE BLUES. (Genus Polyommatus.)
We now arrive at a numerous genus of elegant and lively little insects, collectively known as the "Blues," though some of them are not blue at all. In their manners, and the localities they inhabit, there is so much in common, that one description of these will answer for nearly every one of them; so that my small available space will be in great part devoted to pointing out the marks of distinction between the various species, ten in number, several of them closely resembling others in general appearance, and requiring some care in their discrimination.
Their caterpillars, which are wood-louse shaped, or onisciform, generally feed on low plants, chiefly of the papilionaceous order; and the butterflies are found in dry meadows, on downs, and in open heathy places. The first species, P. Argiolus, is, however, an exception to the above, both in its food and haunts.
Several species of this genus are often found together. For example, in the Isle of Wight, last August, I took P. Argiolus, Corydon, Adonis, Alexis, and Agestis, all within about one hour, and a space of a few yards square in the corner of a field.
THE AZURE BLUE BUTTERFLY. (Polyommatus Argiolus.)
(Plate XIII. fig. 3, Male; 3 a, Female.)
Colouring:—Upper side, beautiful lilac blue—the male with a narrow black border (fig. 3), the female with a broad one, sometimes extending over the outer half of the wing (fig. 3 a). Under side, very delicate silvery blue, almost white, with numerous small black spots. No red spots.
Caterpillar, green, with darker line on back. Feeds on the flowers of holly, ivy, and buckthorn.
The butterfly appears in May, or sometimes in April, and again in August, frequenting woods and hedges, especially where holly and ivy abound. I noticed immense numbers about the ivied walls of Chepstow Castle.
As the name "Azure Blue" is in general use, I have retained it above, but that of "Holly Blue," sometimes applied to it, is preferable, as its colour is much less an azure blue than that of Adonis.
Localities:—Common in the south, and found as far north as Durham and the Lake District. Not known in Scotland.
THE BEDFORD BLUE, OR LITTLE BLUE. (Polyommatus Alsus.)
(Plate XIII. fig. 4, Male; 4 a, Female.)
This is the smallest of British butterflies, specimens being sometimes seen even smaller than those figured.
Colouring:—Upper side, dark brown, distinctly powdered with blue near the root of the wing in the male, without blue in the female. Under side, pale grey-drab, bluish near the base, marked with rows of black spots in pale rings. No red spots.
Caterpillar, green, orange stripe down back, and streaks of same colour on each side.
The butterfly is out in May and June, and is sometimes seen much later. It is generally met with on limestone or chalky soils; and, from a long list of localities I have looked over, it seems to be distributed over England, Scotland, Wales, and Ireland.
THE MAZARINE BLUE. (Polyommatus Acis.)
(Plate XIII. fig. 5, Male; 5 a, Female.)
Colouring:—Upper side, male, deep purple, or mazarine blue, with a border of black (fig. 5); female, dark brown (fig. 5 a). Under sides of both sexes similar, pale greyish drab, tinged at the base with greenish blue, numerous black spots in white rings. No red spots.
Though this elegant butterfly was frequently met with some years ago, it has lately become one of our rarest species, and I can give no locality where it can be now found. It has been reported as taken lately at Ventnor, Isle of Wight, and somewhere in South Wales, also in other places, but only singly.
Collectors, on visiting any new district, should net all the Blues they are not quite sure are common ones, and this may perchance turn up among them sometimes.
The caterpillar is said to feed on the flower heads of common Thrift (Armeria vulgaris).
The butterfly may be looked for in July.
THE LARGE BLUE. (Polyommatus Arion.)
(Plate XIV. fig. 1.)
This is the largest of all our "Blues," and, next to the last, the rarest, though still taken in some numbers every year.
Colouring:—Upper side, dark blue, granulated with black scales that give it a dull aspect, having a black border, and a series of large black spots across the front wing. Under side, greyish drab, suffused with greenish blue near the body; towards centre, many black spots in indistinct light-coloured rings, and a double border of the same. No red spots.
The caterpillar is unknown.
The butterfly appears in July, frequenting rough, flowery pasture-grounds, but is exceedingly local. A famous place for it is Barnwell Wold, about a mile and a half from the village of Barnwell, near Oundle, Northamptonshire, where the insect was discovered by the Rev. W. Bree many years ago; but it is less abundant there than formerly, from the repeated attacks of collectors, who catch all they can find. Other localities, mentioned in various works, are—Brington, Huntingdonshire; Shortwood, and some other spots, near Cheltenham; Charmouth, Dorsetshire; Dover; Downs near Glastonbury, Somerset; Downs near Marlborough, Wiltshire; Broomham, Bedfordshire; near Bedford; near Winchester.
THE CHALK-HILL BLUE. (Polyommatus Corydon.)
(Plate XIV. fig. 2, Male; 2 a, Female.)
Colouring:—Upper side, male, pale silvery greenish blue, with very silky gloss, and shading off into a broad black border.
Female, dark smoky brown, with a leaden tinge, sprinkled near the body with greenish blue scales of the same colour as the males; border of orange spots, more or less visible. Under side marked as in fig. 2 a, on a brown ground, with a row of red spots near border of hind wing.
The caterpillar (Plate I. fig. 10) is green, striped with yellow on the back and sides.
The chrysalis is brownish, and of the shape shown at fig. 29, Plate I.
The butterfly is out in July and August, frequenting chalky downs, especially in the south, and where it does occur is often extremely abundant. Occasionally it is found off the chalk, having been seen in Epping Forest, decidedly not a chalk district. Other localities are—Croydon; Brighton; Lewes; Dover; Winchester; Isle of Wight; Halton, Bucks; Newmarket; Peterborough; Norfolk; Suffolk; Berkshire; Oxfordshire; Wiltshire; Gloucestershire. At Grange, North Lancashire, it is the commonest "Blue," not on chalk, but limestone.
THE ADONIS BLUE. (Polyommatus Adonis.)
(Plate XIV. fig. 3, Male; 3 a, Female.)
Colouring:—Upper side, male, brilliant sky-blue, without any lilac tinge, bordered by a distinct black line, the fringe distinctly barred with blackish. Female, dark smoky brown, sprinkled near body with pure blue scales the colour of those of male; border of orange spots, more or less visible.
Under side, male, marked as in fig. 3; border of red spots.
Female, almost exactly like that of Corydon (fig. 2 a), but usually has the black spots on the front wing smaller.
This is a most lovely little butterfly, the blue of its upper surface being quite unapproachable among native insects. Mr. Stainton, speaking of the different blues of Corydon and Adonis, happily observes that, "Corydon reminds one of the soft silvery appearance of moonlight, whilst Adonis recalls the intense blue of the sky on a hot summer's day."
Caterpillar like that of Corydon.
The butterfly is double-brooded, appearing first in May and again in August. It is found on the same soils and in most of the localities with the last, but is, I believe, more confined to the south.
THE COMMON BLUE. (Polyommatus Alexis.)
(Plate XIV. fig. 4, Male; 4 a, Female.)
Colouring:—Upper side, male, lilac blue. Female, purplish blue about the centre, brown towards the margins, but the proportions of blue and brown are very variable—sometimes all the wings have a border of orange-red spots, sometimes these are absent from one or both pairs of wings.
Fringe in both sexes white, uninterrupted by dark bars.
Under side, male, marked as in fig. 4, and hardly to be distinguished from under side of male Adonis, except by the ground colour, which is paler and greyer than in Adonis. Female, same pattern as male, but coloured with warmer tints—more like male Adonis.
This very pretty little insect is the blue butterfly one sees everywhere, abounding in meadows, on heaths and downs, and not at all confined to chalky soils, like some other "blues."
The caterpillar is green, with darker stripe on the back, and white spots on each side. It feeds on Bird's-foot Trefoil and other leguminous plants.
The butterfly is to be found almost constantly from the end of May to the end of September, being double-brooded.
THE SILVER-STUDDED BLUE. (Polyommatus Ægon.)
(Plate XIV. fig. 5, male; 5 a, Female.)
Colouring:—Upper side, male, purplish blue (rather deeper than that of Alexis), with a rather broad black margin. Female, dark brown, sometimes slightly tinged with blue, and bordered on the hind wings with dull orange spots; but these are often absent.
Fringe white, not barred with black. Under side, near the margin of the hind wings, and between that and the orange border spots, are several metallic spots, of a bluish tint, whence the insect has its name of "Silver-studded."
The caterpillar is brown, with white lines. Feeds on broom and other plants of the same order.
The butterfly appears in July and August, and is very frequently met with throughout the country on heaths, commons, and downs, both on sandy and chalky soils. In many places it is the commonest of the "Blues." It has been found at Epping; Coombe Wood; Darenth Wood; Box Hill; Ripley, Surrey; Brighton; Lewes; Deal; Lyndhurst; Blandford; Brandon, Suffolk; Holt, Norfolk; Birkenhead; Bristol; Sarum, Wiltshire; Lyme Regis; Parley Heath, Dorsetshire; Manchester; York; several places in Scotland.
THE BROWN ARGUS. (Polyommatus Agestis.)
(Plate XIV. fig. 6.)
Though this butterfly and the next are classed among the "Blues," from their possessing the same structure and habits, there is no trace of blue in the colouring of either sex, as in all the preceding species of Polyommatus.
In this species the colour of both sexes on the upper side is a warm, dark brown, having on all the wings a border of dark orange spots. The female hardly differs from the male, except in having this border broader, and more extended on the front wing; where, in the male, it is sometimes very indistinct. The under side much resembles that of the female of Alexis, the border of orange spots being even more distinct on the front wing than on the hind one. It will be observed on referring to Plate XIV. that on the under sides of all the butterflies there figured, there is an irregular black spot situated near the front edge of the upper wing and midway in its length—this is called the "discoidal spot." It will also be observed that the common Blue (fig. 4) has, on the area of the wing, between the discoidal spot and the root of the wing, two spots, which are absent in this species. This forms a very ready mark of distinction, though it requires a good many words to explain it.
The caterpillar, which feeds on Erodium Cicutarium, and perhaps on Helianthemum (Rock Cistus), is green, with pale spots on the back, and a brownish line down the middle.
The butterfly appears in May and June, and again in August, and is common in very many localities in the south, being particularly abundant on the downs of the south coast and the Isle of Wight.
THE ARTAXERXES BUTTERFLY. (Polyommatus Artaxerxes.)
(Plate XIV. fig. 7.)
Colouring, same as in the last species (Agestis); but on the upper surface, the orange border-spots are often hardly perceptible on the front wing, and there is a distinct white spot in the centre of the front wings. The under side also is precisely like that of Agestis, with the black spots removed from the centre of the white rings, which are thus changed into large white spots, as shown in the figure.
There has been a great deal of discussion among entomologists, as to whether this be a distinct species, or only a variety of Agestis. I believe it to be the latter, but do not attach much importance to the question; and as this butterfly is found under the name of Artaxerxes, in almost every cabinet, and is rather a famous little insect, I have thought it best to give it a separate heading under its usual title, and collecting readers may still label it in their cabinet either as above, or as "P. Agestis, var. Artaxerxes," and probably will be equally right either way.
The popular nature and limited extent of this work will not, however, admit of the subject being entered into scientifically, and I can only here state that I have seen specimens from various parts of the country, that include every intermediate variety between the ordinary Agestis of the south, and the Artaxerxes of Scotland. The Durham Argus, formerly called P. Salmacis, forms one of these gradations.
Against the idea of Agestis and Artaxerxes being one species, it has been objected, that the former is double, the latter single brooded. What of that? Plenty of species that are double-brooded in the south of Europe are well known to become single-brooded in a more northern situation.
The caterpillar is said to be exactly like that of Agestis. It feeds on Helianthemum vulgare (Rock Cistus).
The butterfly is found in July and August in several parts of Scotland, and the north of England. Arthur's Seat, Edinburgh, has been long noted for producing it.