British Butterfiles Part 8

"One of the largest flights of b.u.t.terflies ever seen in this country, crossed the Channel from France to England on Sunday last. Such was the density and extent of the cloud formed by the living ma.s.s, that it completely obscured the sun from the people on board our Continental steamers, on their pa.s.sage, for many hundreds of yards, while the insects strewed the decks in all directions. The flight reached England about twelve o'clock at noon, and dispersed themselves inland and along sh.o.r.e, darkening the air as they went. During the sea-pa.s.sage of the b.u.t.terflies, the weather was calm and sunny, with scarce a puff of wind stirring; but an hour or so after they reached _terra firma_, it came on to blow great guns from the S. W., the direction whence the insects came."

A contemporary account states that these were the small white b.u.t.terflies (_Pieris Rapae_).

The smaller b.u.t.terfly with more dusky markings, formerly known as _P.

Metra_, has been recently proved to be merely a variety of _Rapae_, a Mr. J.

F. Dawson having reared a brood of caterpillars all _exactly similar_ in appearance, which eventually produced every variety of _P. Rapae_ and _P.

Metra_.

Mr. Curtis, in his "Farm Insects," mentions the capture, near Oldham in Lancashire, of a male specimen, which had all the wings of a _bright yellow_ colour.

Most juvenile b.u.t.terfly hunters, unblest by scientific knowledge of insect life, imagine that this and the last owe their difference in size simply to their being old and young individuals of the same name; forgetting--or, rather, never having heard--that b.u.t.terflies never grow in the slightest degree after once getting their winged form; only as caterpillars do they grow. {86}

The male is distinguished from the female by having only _one round black spot_, or sometimes none, on each _upper_ wing, whilst the female is spotted as in the engraving. The under side of the hind wings is dull yellow, lightly powdered with black scales.

The _b.u.t.terfly_ is seen during nearly the whole of the summer, and is found almost everywhere.

THE GREEN-VEINED WHITE b.u.t.tERFLY. (_Pieris Napi._)

(Plate IV. fig. 4.)

Is so called from the greenish tint that _often_ borders the veins or nervures on the _under_ side of the _hind_ wing; but the name is _not always_ an appropriate one, for a large proportion of the specimens met with have the veinings grey, and not at all green; but the fact is, that the ground colour varies greatly, from creamy white to full buff, or bright clear yellow; in the latter case it is, that the minute black scales which border the course of the nervures, covering over the yellow, produce a grey-green effect on the eye.

The size also is very variable. I have a specimen that expands two inches and two lines across, from tip to tip, and have seen another not larger than a small Copper b.u.t.terfly--little more than one inch from tip {87} to tip. The intensity of the dark markings, on both the upper and under sides, is also subject to much variation.

But, under all these circ.u.mstances, the presence of dark cloudy veins on the under side--appearing, but less distinctly, on the upper side--will at once distinguish it from the last species, the only one with which it can possibly be confounded.

The _male_ has only _one round spot_ on the _front_ wings; the _female_ being marked as in the plate.

Both in woods and cultivated grounds we meet with this b.u.t.terfly commonly enough, most abundantly in May and July, though it may be found from April to August.

The _caterpillar_ feeds on the same tribe of plants as the two last, but is supposed to be especially attached to the Rape (_Bra.s.sica Napus_), whence its specific name. Its colour is green, with yellow spots round each spiracle, which is itself tinged with red.

Two varieties of this were formerly ranked as distinct species, under the name of _P. Sabellicae_ and _P. Napae_.

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THE BATH WHITE. (_Pieris Daplidice._)

(Plate IV. fig. 5, Female.)

Of all the members of this white-winged genus that inhabit Britain, this is at the same time the most beautiful and the rarest. The capture of a Bath White is an entomological "event," and the day thereof is a red-letter day in the fortunate captor's life.

On the opposite coast of France, however, and generally on the Continent, far from being a rarity, this is one of the commonest b.u.t.terflies--a fact difficult for an English collector, removed by only a few miles of sea, to realise, or reconcile with the _extravagant_ value and importance attached to a true "British specimen."

The remark made under the head of the Black-veined White, as to that eluding the net of the novice, by its resemblance to a common kind, will apply with still greater force to this one; for I suppose there are few even of the tolerably experienced "hands" who could tell this from the two last described insects, at a short distance. One curious circ.u.mstance bearing on this is, that a large per centage of the Bath White captures in this country have been made by juvenile beginners, who hunt and catch _everything_ they see, Common Whites and all. {89}

This fact should encourage the collector, especially when at work on the south-east coast, to net all the middle-sized Whites that come within reasonable distance--of course letting them off again, if they are not of the right sort.

The wing markings on both the upper and under sides are, though simple, extremely elegant and chaste. The _female_, which is the s.e.x figured, has the upper wings beautifully spotted with black. The hind wings are bordered with a _row of black spots_, and clouded towards the centre with a faint tint of the same.

The male is distinguished by the absence of the black spot nearest to the lower margin of the front wing, and of the black marginal spots and grey clouding of the hind wings. The markings of the under surface, however, show through their substance rather plainly.

In both s.e.xes, the ground colour of the wings is milk-white. But the chief decoration is reserved for the under surface, which is chequered, in a manner not easily described, with a soft but rich green tint upon white, relieved here and there by a few black touches.

We are informed by Lewin, that it was named the Bath White from a piece of needlework executed at Bath, by a young lady, from a specimen of this insect, said to have been taken near that city. But the south-eastern corner of England, and more especially on the coast, seems to be the head-quarters of this valued fly,--lending probability to the supposition entertained {90} by many, that a large proportion of those taken here have migrated or been blown across the Channel; though I believe it sometimes breeds here, and that the caterpillars have, on one or two occasions, been found in this country.

The b.u.t.terfly has been taken several times at Dover, Margate, and other places on the Kentish coast; at Lewes; Whittlesea Mere, Cambridge; Worcester, and near Bristol.

The _caterpillar_, which is to be found in June and September, is bluish with black spots, a pale yellow line on each side, and two of the same colour on the back. M. Le Plastrier reared a number of them, feeding them on the leaves of the Wild Mignonette (_Reseda lutea_). It also feeds on Weld (_Reseda Luteola_).

The _chrysalis_ very much resembles that of the Small Garden White, and is totally unlike that of the next, the Orange-Tip, with which it has been by some entomologist united into another genus (_Manicipium_).

_Daplidice_ is a slow insect--slower than the Common Whites--and it is an easy matter to catch it, when recognized, which the peculiarly heavy flight might aid one in doing.

May and August are the months in which to look after this gem of the _Pontia_ genus.

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THE ORANGE-TIP b.u.t.tERFLY. (_Euchloe Cardamines._)

(Plate V. fig. 1, Male; 1_a_, Female.)

Few vernal ramblers in the country, whether entomological or no, can fail to have noticed, and been charmed by, this merry blossom-like insect, as it gaily flits along by hedge-row and wood-side, pausing anon to taste its own sweet flowers of May, and looking, even when on the wing, so unlike any other of our native b.u.t.terflies. Truly it is an exquisite and loveable little creature, this Orange-Tip--sometimes styled the Wood Lady; but this latter t.i.tle is somewhat awkward in its application, inasmuch as the "_lady_" insect is entirely without the characteristic _orange_ adornment, and would hardly be suspected as being the same species with her handsome lord.

The _male Orange-Tip_ needs no description, for the purpose of recognition, beyond that conveyed by his name; but as the _female_ is less known, and has been on several occasions mistaken for the rare Bath White (_Daplidice_), it will be well to point out her chief distinguishing characters. The difference between the two insects certainly is obvious enough, when the two are _seen_ together, but their written descriptions read rather alike. {92}

The female _Cardamines_ has the wings white _above_, with a greyish black tip, and a _small oval_, or _crescent-shaped black spot_ (much smaller than that of Daplidice) near the _centre_ of the front wings; _beneath_, a white ground, with green marblings, that are much more sharply defined than those in _Daplidice_. Near the centre of the front wing is a _clear black spot_, corresponding in position with that on the upper surface, _and not shaded off with green, as in Daplidice_.

We speak of the _green_ marblings of this species--and, to the naked eye, they do appear to be of quite a bright green--but under a microscope or powerful lens that colour disappears, being resolved into a combination of bright yellow and pure black scales, which, with the dazzling snow-white ground scales that surround them, form a microscopic tableau of extraordinary beauty. This can, however, only be seen by daylight, for under artificial light the yellow, on which the whole effect depends, is entirely lost.

The _caterpillar_ is slightly hairy, and green, with a white stripe on each side. It has been generally stated that the _Cardamine impatiens_ is the common food plant of this species, _apropos_ of which I will quote the following communication from Mr. Doubleday to the editor of the _Zoologist_:--

"In reply to your query about the food of the larva of _Cardamines_, I may say that I have found it upon several plants. I believe that _Cardamine pratensis_ (common cuckoo-flower) is the one on which the eggs {93} are most frequently deposited, but the greater part of the _larvae_ must perish in this neighbourhood, because the fields are mowed before the larvae are full-grown. I have very often seen the larvae on the seed-pods of _Erysimum Alliaria_, and have several times found the _pupae_ on the dead stems of this plant in winter; I think that it is the princ.i.p.al food of Cardamines at Epping; it also probably feeds on _E. barbarea_, and other similar plants. Some years ago we used to have a quant.i.ty of a large single rocket in the garden, and there was always a number of the larvae of _Cardamines_ feeding on the seed-pods. _Cardamine impatiens_ is so local a plant _that it cannot be the common food of the larvae of Cardamines_."

The _chrysalis_ is of the very singular shape shown at fig. 17, Plate I., a shape quite unique among British b.u.t.terflies, though that of the next slightly approaches it. It is to be looked for in autumn and winter on the dry, dead stems of the plants named in the foregoing paragraph.

The perfect b.u.t.terfly, which is very common throughout the country, is met with from the end of April to the end of May or beginning of June.

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