British Butterfiles Part 7

The same localities--viz. the south and south-east coast, and the adjacent district--that are most prolific in its near relative, _Edusa_, likewise furnish this species in the greatest plenty; but this is by far the rarer species of the two, and, either by coincidence, or in obedience to some direct law, several successive periods of its abundance have been septennial, or have occurred once in seven years. Thus the years 1821, '28, '35, '42, '49, and '56 are noted in entomological records as having produced it in great numbers.

On the coast of France, opposite to our own, it is one of the common b.u.t.terflies, and it is not improbable that it frequently makes the pa.s.sage of the Channel. The maritime habits of both this and _Edusa_ are well known, and I have frequently seen the latter flying out to seawards, and coquetting with the waves, till the eye could follow the golden speck no longer. Taking advantage then of a favouring wind, its naturally strong {77} and rapid flight would quickly take it across the few miles of sea that separate us from the Gallic sh.o.r.e.

_Hyale_, whose flight is at least as strong as _Edusa's_, and whose salt-water tastes are similar, doubtless acts in the same manner.

The northward range of this species is more limited than that of _Edusa_, but it has been taken singly near York, Manchester, and a few other northern localities. In the lucerne fields near Brighton, a dozen or more have been sometimes captured in one day.

The _caterpillar_ is of a sea-green colour, with four yellow lines, two along the back and one on each side; and is to be found, in June and July, feeding on lucerne and other plants of the same natural order.

The _chrysalis_ is very similar to that of _Edusa_, green, with a yellow stripe.

In this country, the _b.u.t.terfly_ first appears in August; but on the Continent it seems to be double-brooded, being found in May as well as in August.

THE BLACK-VEINED OR HAWTHORN b.u.t.tERFLY. (_Aporia Crataegi._)

(Plate IV. fig. 1.)

When on the wing, this species might easily be mistaken by the inexperienced for the common Cabbage {78} White; and, by virtue of this _incognito_, does in all probability often escape from the terrors of the net, which would speedily entrap him, were his real character known to the young hunter; for this b.u.t.terfly is one of those called, in entomological slang, "_a good thing_"--a term expressive neither of superior excellence nor beauty, but meaning that the insect can't be met with everywhere, or every day, and when seen is always to be caught.

A closer view, however, shows it to be very distinct from all the other "Whites;" its _decided black veinings on a milk-white ground_, in conjunction with its large size, being sufficient for its immediate recognition.

The outline of the wings, as well as the play of the veining lines on their surface, is extremely elegant. It will be observed, that instead of the feathered fringe that surrounds the wings of most b.u.t.terflies, they are bordered in this species by a stout nervure, forming a sharp black outline, and giving a peculiarly chaste finish.

The under side differs in no mentionable respect from the upper--a very rare circ.u.mstance in this tribe. From being very sparingly coated with scales, the wings are semi-transparent, differing much in this respect from those of the Garden White b.u.t.terflies.

The female generally has the veins of the fore wings of a browner tint than in the males.

This b.u.t.terfly is one of the very local species, though its food plants are everywhere to be found, in more or less abundance. {79}

The following localities, among others, have been recorded as producing it:--Herne Bay, and other parts of the Isle of Thanet, plentifully; near Faversham, Kent; Horsham, Suss.e.x; New Forest; Brington, in Huntingdonshire; near Cardiff, South Wales, plentiful.

The caterpillars are gregarious, feeding under cover of a silken web. The hawthorn and the sloe are its chief food plants in this country, but it is here too rare an insect to do much damage. Not so, however, on the Continent, where it is extremely common, and is cla.s.sed among noxious insects, committing great devastation among various fruit trees, especially the apple, pear, and cherry.

But even in this country the insect is occasionally met with in great profusion, but only in isolated spots. Mr. Drane, writing from Cardiff to the _Zoologist_, says, "In the middle of April (1858) I found the _larvae_ feeding by thousands upon insulated shrubs of _Prunus Spinosa_ (Common Sloe), eating out the centres of the unexpanded buds, or basking in the sun upon their winter webs."

The body of the adult _caterpillar_ is thickly clothed with whitish hairs, is leaden grey on the side and underneath, black on the back, and marked with two longitudinal reddish stripes. Found from the middle of April to the end of May.

The _chrysalis_, shown at fig. 14, Plate I., is greenish white, striped with yellow and spotted with black.

The _b.u.t.terfly_ appears in June.

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THE LARGE GARDEN WHITE b.u.t.tERFLY (_Pieris Bra.s.sicae._)

(Plate IV. fig. 2.)

Why this b.u.t.terfly should so far outnumber every other native species (excepting, perhaps, the more rural Meadow Brown), is a question beyond our power to answer satisfactorily. Certainly, the food plants of the caterpillar--cabbages, cresses, and their tribe--are universally met with; but then we find there are other insects whose food plant is equally plentiful and widespread, and yet they are nevertheless very rare or local.

This is pre-eminently the domestic b.u.t.terfly, abounding in suburban gardens, and at times penetrating into the smoky heart of London, and then even the young "St. Giles's bird," whose eyes were never gladdened by green fields, gets up a b.u.t.terfly hunt, and, cap (or rag) in hand, feels for the nonce all the enthusiasm of the chase in pursuit of the white-winged wanderer, who looks sadly lost and out of place in the flowerless, brick-and-mortar wilderness.

This and the next species are the only British b.u.t.terflies who can be charged with committing any appreciable amount of damage to human food and property. In the winged state, indeed, it is utterly harmless (like all other b.u.t.terflies); but not so the hungry caterpillar progeny, as the gardener knows too well when he looks {81} at his choice cabbage rows all gnawed away into skeletons.

In some seasons and places they multiply so inordinately and prodigiously as to deserve the t.i.tle of a plague of caterpillars, and several remarkable instances of this phenomenon are on record.

A note in the _Zoologist_, p. 4547, by the Rev. Arthur Hussey, gives us the following:--"For the last two summers many of the gardens of this village have been infested by caterpillars to such an extent that the cabbages have been utterly destroyed." When the time for changing to the chrysalis state arrived, the surrounding buildings presented a curious appearance, being marked with long lines of the creatures travelling up the walls in search of a suitable place of shelter for undergoing their transformation. A great number of the caterpillars took refuge in a malt-house, from which they could not escape as b.u.t.terflies, the result being that for several weeks the maltster swept up daily many hundreds of the dead insects.

In 1842, a vast flight of white b.u.t.terflies came over from the Continent to the coast about Dover, and spreading inland from thence, did an immense amount of damage to the cabbage gardens; but so effectually did the ichneumon flies do their work, that an exceedingly small proportion of the caterpillars, resulting from this flock of immigrants, went into the chrysalis state, nearly all perishing just before the period of change.

Those small, silky, oval objects, of yellowish colour, {82} frequently found in groups on walls and palings, are the _coc.o.o.ns_ of these useful little flies, spun round about and over the remains of the dead caterpillar their victim. "These," as Mr. Westwood observes, "ignorant persons mistake for the eggs of the caterpillar, and destroy; thus foolishly killing their benefactors."

Happily these devastating caterpillars have plenty of enemies to prevent their continued multiplication, and to reduce their number speedily when it exceeds certain limits. Besides the ichneumons, mentioned above, the feathered tribes do much towards keeping them down. Mr. Haworth, in his "_Lepidoptera Britannica_," says, with reference to this: "Small birds destroy incredible numbers of them as food, and should be encouraged. I once observed a t.i.tmouse (_Parus major_) take five or six large ones to its nest in a very few minutes. In enclosed gardens sea-gulls, with their wings cut, are of infinite service. I had one eight years, which was at last killed by accident, that lived entirely all the while upon the insects, slugs, and worms which he found in the garden."

The pretty _egg_ of this b.u.t.terfly is figured on Plate II. fig. 1: it may be found commonly enough, with a little searching, on cabbage-leaves, either at the end of May or beginning of August.

The _caterpillar_, which, besides cabbages, consumes various other cruciferous plants,--also Tropaeolums, or, as they are erroneously called, "Nasturtiums,"--is green, {83} shaded with yellow on each side, and covered with black points, on each of which is situated a hair.

By way of compensation for the damage it inflicts, it has been suggested that a durable green dye might be extracted from the caterpillars of cabbage b.u.t.terflies, since it is extremely difficult to eradicate the stain made by a crushed caterpillar on linen. If this strange and novel dye should ever take its place among the vagaries of fashion, the shopkeepers could find a familiar French name, as the word _chenille_, applied to another commodity, means simply "caterpillar," so "_chenille green_" would be the phrase for the colour afforded by smashed caterpillars.

The _chrysalis_ (Plate I. fig. 15) may be found almost anywhere, laid up under ledges of garden walls, doorway, or any convenient projection, not too far from the creature's food. Wanting an individual just now, to sit for his portrait, I had only to step out of my door, and within a hundred yards espied a candidate for the distinction, ready to hand, under the coping-stone of a gate-post.

A _female_ specimen of the b.u.t.terfly is figured on Plate IV. fig. 2. The _male_ may be readily distinguished by the _absence of the black spots and dashes on the upper side of the front wings_.

The winged insect may be seen throughout the warm season from April to August.

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THE SMALL GARDEN WHITE. (_Pieris Rapae._)

(Plate IV. fig. 3.)

Outwardly resembling the last in almost every respect but that of its inferior size, this species shares the gardener's malediction with its larger, but perhaps less destructive, relative; for the caterpillar of _Rapae_, though smaller, bores into the very heart of the cabbage, instead of being content with the less valuable outer leaves, as _Bra.s.sicae_ is.

From this pernicious habit the French call this grub the _ver du coeur_.

The colour of this _caterpillar_ is pale green, with a yellow line along the back, and a dotted one of the same colour on each side.

The _chrysalis_ is nearly like that of the last in shape, but of course smaller, and is of a more uniform brownish or yellowish tint.

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

{85} This b.u.t.terfly occasionally multiplies immensely, and is given to migrating in vast armies to distant settlements, sometimes crossing the sea to effect this purpose. Here is an extract from a Kentish newspaper, describing an occurrence of this phenomenon:--