British Butterfiles Part 6

Each probably finds its followers, and to the occasional prevalence of the more tender sentiment, are probably owing many of those stray Swallow-Tails that turn up here and there in unlikely places.

The chrysalides, for rearing, may be obtained in the autumn or winter, either from entomologists resident in the localities of the b.u.t.terfly, or more generally and certainly from the London or Cambridge dealers, who will send them into the country by post for a few pence each.

The flight of this species is rapid and powerful, and it has a habit of soaring loftily.

In this country its head quarters are in the fens of Cambridgeshire, Norfolk, and Huntingdonshire. It has been found in some abundance near Cambridge, Norwich, Yaxley, Whittlesea Mere, Burwell, and Hornsey Fens; also singly in Lancashire, at Battersea, Pulborough in Suss.e.x, near Ashford in Kent, at Balcombe, Isle of Wight, Hampshire, near Chatham, at Southend, Ess.e.x, and on the Cliffs of the South Coast. {67}

From its local character, this is of course one of the species that the collector can hardly expect to meet with, except he live in one of the districts given above as its head quarters. In these, however, it is abundant enough, and the first sight of a number of these grand insects on the wing must be enough to gladden the eye of any naturalist.

This b.u.t.terfly comes out first in May, and is met with from that time till August.

THE BRIMSTONE b.u.t.tERFLY. (_Gonepteryx Rhamni._)

(Plate III. fig. 2.)

Though one of the commonest of our native b.u.t.terflies, this, like numberless other very common things, is also one of the loveliest, both in the graceful outline of its wings, and in the lively hue that overspreads their surface; charms the more to be appreciated, as this insect is one of the few that do not wait for the full bloom of summer ere they condescend to make their appearance, but in the earliest, chill months of spring, and even in the dead winter season, the country rambler is sometimes gladdened by its gay flight; and in fact there is not one winter month that is not occasionally enlivened by this flying flower, when a day of unwonted mildness and sunshine tempts it from its winter retreat. {68}

Until very recently it had always been stated by entomologists, that the Brimstone b.u.t.terfly was "double-brooded" (a term meaning that it went through _two whole cycles of existence_, from the _egg_ to the _perfect insect_, in _one year_), one brood appearing in May, and the other in the autumn.

But it is now established, on very satisfactory evidence, that _one brood only is produced, and that, the autumnal one_. A considerable number of these survive the winter in some place of concealment, and coming out again in the spring form the so-called spring brood. Many of these hybernators are found to be in very fair condition in the spring, but in general they lack the perfect freshness and bloom of those taken in autumn; the wings of those I have taken at this period are often semi-transparent, from having lost feather, and frequently are spotted and discoloured, as if by mildew; a sign probably of their owners having wintered in damp lodgings.

Mr. Douglas states that they get very fat and full of honey before consigning themselves to their long winter's sleep; evidently an instinctive provision against the waste of substance that must of necessity accompany all, even the most sluggish vitality: in this respect following the same instinct that leads bears, and other hybernating animals, to fatten up to their utmost stretch before retiring for the season.

[Ill.u.s.tration: IX.]

{69} The _eggs_ should be sought for in the month of May, or a little earlier or later, on the buds and young shoots of the two species of Buckthorn (_Rhamnus Frangula_ and _R. Catharticus_). When examined with the microscope, these are found to be very pretty objects of conical form, with sculptured ribs on the sides.

The _caterpillar_ that results from these, when it grows up, is of a fine green colour, s.h.a.greened over with black points, and shading off into a paler line along the side. Its shape is represented at Plate I. fig. 2. It is found on the _young_ buckthorn foliage that forms its food.

The _chrysalis_ is of the remarkable shape shown on Plate I. fig.

13,--green, marked with yellow. It remains in this state for about twenty days, when the perfect b.u.t.terfly appears.

The general colour of the male Brimstone b.u.t.terfly is a clear, brilliant yellow, much like that of the Daffodil, its contemporary; and in the centre of each wing is a small spot of rich orange-colour. A very beautiful feature to be remarked in this b.u.t.terfly is the silken mane, so to speak, composed of long hairs of silvery gloss and whiteness, which are arranged as if combed up from the sides of the thorax, so as to meet in a crested form over the top.

The female chiefly differs from the male in the ground colour of the wings, which are of a pale and very peculiar greenish white tint, rather more deeply tinged with yellow at the extremities of the wings.

As the male, from his colour, bears the name of "Brimstone," or "Sulphur,"

the complexion of his mate may be accurately compared to the tint of another {70} sulphureous preparation, called by druggists "milk of sulphur."

The only noticeable variation this b.u.t.terfly is subject to in this country is in the size of the orange wing-spots, which are sometimes greatly enlarged.

In a well-marked variety, common in the south of Europe, Madeira, &c., this enlargement reaches a great development, nearly the whole of the _upper_ wings being suffused with a deep orange, though in all other respects the insect does not differ from our common form. This beautiful variety has been described as a different species under the name of _Gonepteryx Cleopatra_; but M. Boisduval has proved that they are identical, by rearing both the ordinary _Rhamni_ and the _Cleopatra_ from the same batch of eggs.

The female _Cleopatra_ does not differ materially from _Rhamni_. I look on this variety as very interesting, as a probable instance of the direct effect of increased warmth of climate in intensifying colour.[9]

Plentiful as this b.u.t.terfly is in all the southern counties, and extending in more or less abundance as {71} far northwards as the lake district, it there becomes scarce; and I can find no instance of its having occurred in Scotland.

Of course, its prevalence in any district is naturally regulated by the abundance of its food-plants, the buckthorns.

Gardens, fields, and lanes are equally the resort of this favourite insect; and there the newly-hatched specimens are to be found on the wing from August to October.

THE CLOUDED YELLOW, OR CLOUDED SAFFRON. (_Colias Edusa._)

(Plate III. fig. 3, Male; 3A, Female.)

This richly-coloured and nimble-winged fly is ever the darling of the collector. None make a finer show in the cabinet, and few tempt pursuit more strongly than does this golden beauty when on the wing.

For many years past, and up to quite a recent period, the appearance of this b.u.t.terfly in any abundance was a phenomenon only occurring at uncertain periods, separated by intervals of several years. In one season, perhaps, hardly a solitary specimen would be seen, and in the very next, a swarm of them would spread over the southern counties, delighting the fly-catcher and puzzling the naturalist to find a sufficient reason for {72} this sudden burst of insect-life. Whether the eggs lay dormant for years, till hatched under peculiarly favourable conditions; or whether every now and then a few individuals were tempted to cross the Channel from the Continent by some attraction unknown to us, or were, _nolens_, _volens_, blown hither by the wind, and then deposited eggs which produced the next year's troop of b.u.t.terflies; or, lastly, whether an agency was at work here, of whose nature we are entirely ignorant,--all these are questions that still remain to be answered. There is, I believe, no foundation for the opinion sometimes held by entomologists, that this species prevails at _regular_ periods, such as once in four, or once in seven years. In fact, for the last two or three years its permanent residence and appearance among us seems to be established, while, at the same time, its northward range has been greatly extended, a considerable number having been taken even _in Scotland_--its existence in that country having been previously quite unheard of.

The environs of London, especially on the south side, have been abundantly visited by this charming insect; but its tastes have a decidedly maritime tendency, and we find it has a marked preference for the _South Coast_; abounding, again, more especially towards the eastern end. Its favourite resorts are clover and lucerne fields, though dry flowery meadows, open downs, and the sides of railway-banks are also the scenes of its lively flight--for _Edusa_ has indeed a lively flight, and his pursuer has need of the "seven-league boots," with the hand of {73} Mercury, to insure success in the fair open race, if that can be called a fair race at all, between a heavy biped, struggling and perspiring about a slippery hill-side, such as _Edusa_ loves,--and a winged spirit of air, to whom up-hill and down-hill seem all one.

In truth, the best way to get _Edusa_ is to watch and mark him down on a flower, then creep cautiously up till within range, raise the net quietly, and _strike rapidly downwards_ over the insect, who usually darts _upward_ when struck at; and, in nine cases out of ten, _Edusa_ will be fluttering under the net. It is not the most heroic style of sport, this, but it fills the boxes admirably.

The _caterpillar_ is of a deep green colour, having on each side a white line, marked with yellow and orange. It may be sought for in June and July, on various plants of the leguminous order, which form its food, such as None-such Trefoil (_Medicago lupulina_), Lucerne (_M. Sativa_), and Clover.

The _chrysalis_ is in shape between that of the Brimstone, and Cabbage b.u.t.terfly, green with a yellow stripe, and rust-coloured dots.

The _b.u.t.terfly_ seldom is seen on the wing till July, but August is its great season; and it lingers with us till late in autumn.

I remember the pleasure with which, on a chill, stormy day in October, I watched the sports of a pair who were my sole companions while sketching, in a remote, rocky nook of the South Welsh coast. Very {74} battered and weather-worn were the pretty creatures, but still retaining much of the golden bloom of their summer dress.

The Clouded Yellow has been found hybernating in the c.h.i.n.k of an old wall at the end of February, but I am not aware of its coming out again in the spring, like the Brimstone.

The ground tint of the wings is an exceedingly rich orange-yellow, or saffron colour, surrounded by a border of very dark brown, sometimes nearly black. This border is marked, in the male, with thin yellow _lines_, and in the female with _paler yellow spots_. There is a beautiful rose tint in the fringe of the wings and on their front edge. Underneath the wings are paler yellow, taking a citron hue in some parts, and marked with black and brown; in the centre of the under wings is a brown-circled silvery spot.

There is a peculiar and constant _variety of the female_, in which all the yellow portion of the upper surface is replaced by a _greenish white_ tint; but in every other respect the insect agrees with the common form of _Edusa_. This interesting variety was formerly ranked as another species, under the name of _C. Helice_; but it is a curious fact that no corresponding variety of the male has ever been observed; and last year I captured a pair together--a white female and common orange male--who were on those terms of tender intimacy which are generally supposed to betoken ident.i.ty of species. {75}

Varieties of the female are also met with, of various intermediate shades of colour between the white and the ordinary orange.

Yet is it not possible that all these varieties may be mules between _C.

Edusa_ and _C. Hyale_ (the next species), the males of which are often seen pursuing the lady _Edusas_? but if so, as indeed it would be on any other hypothesis, it is hard to account for the unvarying character of the male.

This b.u.t.terfly is also called the Clouded Saffron.

THE CLOUDED SULPHUR, OR PALE CLOUDED YELLOW b.u.t.tERFLY. (_Colias Hyale._)

(Plate III. fig. 4.)

We may, in general, readily distinguish this elegant insect from the last species--the females of which it rather resembles in its markings--by the difference in the ground tint of the wings, which in this vary from primrose or sulphur yellow to a greenish white.

There is, however, some risk of confounding this with the white variety of _Edusa_ (_Helice_), a mistake often committed by young entomologists; so it will be well to point out the most prominent distinction between the two; and this is easily done, by observing that in _Edusa_ the dark border of the upper wings is of nearly {76} equal breadth along the whole of the outer margin, and _at the lower corner is continued inwards for a short distance_; whilst in _Hyale_ this border _narrows rapidly, and disappears before reaching the lower corner of_ the wing. Also the dark border of the hind wings is much broader in _Edusa_ than in _Hyale_. Here we have distinctive marks, quite independent of the ground colour of the wings.

The s.e.xes of this b.u.t.terfly are nearly alike in their markings, the chief difference being in the yellower ground tint of the males.