Butterflies and Moths Part 16

Probably the number of blank s.p.a.ces will at first suggest an almost hopeless task, but a few years of careful searching and rearing will give you heart to continue your interesting work.

Arrange all the insects in perpendicular rows. Put the names of each section, tribe, family, and genus _at the head_ of their respective divisions, and the names of the species below each insect or series of insects. The opposite plan, in which the circles represent the insects themselves, will make this clear.

Three or four specimens of each species are generally sufficient, except where variations in colouring are to be exhibited. Wherever differences exist in the form or markings of the s.e.xes, both should appear; and one specimen of each species should be pinned so as to exhibit the under side.

Finally, each drawer or box should have a neat label _outside_ giving the name or names of the divisions of insects that are represented within. This will enable you to find anything you may require without the necessity of opening drawer after drawer or box after box.

PART III

BRITISH b.u.t.tERFLIES

We have now treated in detail of the changes through which b.u.t.terflies and moths have to pa.s.s, and have studied the methods by which we may obtain and preserve the insects in their different stages. I shall now give such a brief description of individual species as will enable the reader to recognise them readily. We will begin with the b.u.t.terflies.

CHAPTER XII

_THE SWALLOW-TAIL AND THE 'WHITES'_

Family--PAPILIONIDae

_The Swallow-tail_ (_Papilio Machaon_)

Our first family (_Papilionidae_) contains only one British species--the beautiful Swallow-tail (_Papilio Machaon_), distinguished at once from all other British b.u.t.terflies by its superior size and the 'tails'

projecting from the hind margin of the hind wings.

This beautiful insect is figured on Plate I, where its bold black markings on a yellow ground are so conspicuous as to render a written description superfluous. Attention may be called, however, to the yellow scales that dot the dark bands and blotches, making them look as if they had been powdered; also to the blue clouds that relieve the black bands of the hind wings, and the round reddish orange spot at the a.n.a.l angle of each of the same wings.

It appears that this b.u.t.terfly was once widely distributed throughout England, having been recorded as common in various counties, and has also been taken in Scotland and Ireland; but it is now almost exclusively confined to the fens of Cambridgeshire, Huntingdonshire, and Norfolk. Occasionally we hear of the capture of single specimens quite outside these localities, sometimes even in most unlikely spots, where its food plant does not abound. But we know that _Machaon_ is a general favourite with entomologists, and that it is sent in the pupal state, by post, to all parts of the kingdom; so that the occasional capture of the insect far beyond the borders of its haunts is probably the outcome of an escape from prison, or of the tender-heartedness of some lover of nature who could not bear to see such a beautiful creature deprived of its short but joyous, sunny flight.

You cannot hope to see this splendid b.u.t.terfly on the wing unless you visit its haunts during its season--May to August; but the pupae may be purchased for a few pence each from most of the entomological dealers; and if you obtain a few of these and watch them closely, you may be fortunate enough to see the perfect insect emerge from its case, and witness the gradual expansion of its beautiful wings.

The pupa (Plate VIII, fig. 7) itself is a most beautiful object. Its colour is a pale green, and it is fixed to its support by the tail, and further secured by a very strong silk band.

The larva (Plate VIII, fig. 1), too, is exceedingly beautiful. Its ground colour is a lovely green, and twelve velvety black rings mark the divisions between the segments. Between these are also black bars, all spotted with bright orange except the one on the second segment.

A remarkable feature of this larva is the possession of a forked, Y-shaped 'horn,' that is projected from the back, just behind the head, when the creature is alarmed. If it is gently pressed or irritated in any way, this horn is thrust out just as if it were an important weapon of defence. And perhaps it is, for it is the source of a powerful odour of fennel--one of the food plants of the caterpillar--that may possibly prove objectionable to some of its numerous enemies.

The food plants of _Machaon_ are the milk parsley or hog's fennel (_Peucedanum pal.u.s.tre_), cow-parsnip (_Heracleum sphondylium_), and the wild angelica (_Angelica sylvestris_); but in confinement it will also partake of rue and carrot leaves.

The caterpillar of this species may be found in the fens during the greater part of the summer. It turns to a chrysalis in the autumn, and remains in this state throughout the winter, attached to the stems of reeds in the vicinity of its food plants. The perfect insect is first seen in May, and is more or less abundant from this time to the month of August.

Family--PIERIDae

This family, though known commonly as the 'Whites,' contains four British species that display beautiful tints of bright yellow or orange.

In many respects the _Pieridae_ resemble the last species. Thus the perfect insects have six fully developed legs; the caterpillars are devoid of bristles or spines; and the chrysalides are attached by means of silky webs at the 'tails,' and strong cords of the same material round the middle.

All the larvae are also cylindrical or wormlike in shape; and their skins are either quite smooth, or are covered with very short and fine hairs, that sometimes impart a soft, velvety appearance.

The members of this family are remarkable for their partiality for certain of our cultivated plants and trees; and are, in some cases, so abundant and so voracious, that they are exceedingly destructive to certain crops.

_The Black-veined White_ (_Aporia Crataegi_)

This b.u.t.terfly may now be regarded as one of our rarities. At one time it was rather abundant in certain localities in England, among which may be mentioned the neighbourhoods of Cardiff and Stroud, also parts of Kent, Suss.e.x, Hampshire, Huntingdonshire, and the Isle of Thanet; but it is to be feared that this species is nearly or quite extinct in this country. It is well, however, not to give up the search for it, and if you happen to be in one of its favoured localities of former days, you might net all the doubtful 'Whites' of large size that arouse your suspicions, liberating them again if, on inspection, they do not answer to the description of the species 'wanted.' This course becomes absolutely necessary, since the Black-veined White is hardly to be distinguished from the Common Large White while on the wing.

If you examine a number of British b.u.t.terflies you will observe that in nearly all species the wings are bordered by a fringe of hair, more or less distinct. But the case is different with _Crataegi_. Here they are bordered by a black nervure, without any trace of fringe, thus giving an amount of rigidity to the edges (see Plate I, fig. 2).

The wing rays, or nervures, are very distinct--a feature that gave rise to the popular name of the b.u.t.terfly. In the male they are quite or nearly black, but those of the fore wings of the female are decidedly brown in colour. At the terminations of the wing rays there are triangular patches of dark scales, the bases of which unite on the outer margins of the wings.

Another peculiar feature of this insect is the scanty distribution of scales on the wings. This is particularly so in the case of the female, whose wings are semi-transparent in consequence.

The b.u.t.terfly is on the wing during June and July, at which time its eggs are laid on the hawthorn (_Crataegus Oxyacantha_) or on fruit trees--apple, pear and plum.

A vigorous search of these trees in the proper localities _may_ reveal to you a nest of the gregarious larvae, all resting under the cover of a common web of silk. These remain thus under their silken tent throughout the hottest hours of the day, and venture out to feed only during the early morning and in the evening.

When the leaves begin to fall in the autumn, they construct a more substantial web to protect themselves from the dangers of the winter, and in this they hybernate till the buds burst in the following spring.

They now venture out, at first during the mildest days only, and feed voraciously on the young leaves, returning to their homes to rest. Soon, however, they gradually lose their social tendencies, till at last, when about half or three-quarters fed, they become quite solitary in their habits.

In May they are fully grown, and change to the chrysalis state on the twigs of their food trees.

The larva is black above, with two reddish stripes. The sides and under surface are grey, the former being relieved by black spiracles.

The pupa (page 45) is greenish or yellowish white, striped with bright yellow, and spotted with black.

It is probable that the reader will never meet with this insect in any of its stages. But, though it may have left us, it is still very abundant on the Continent, where it does great damage to fruit trees; and the foreign pupae may be purchased of English dealers.

_The Large White_ (_Pieris Bra.s.sicae_)

We pa.s.s now from one of the rarest to one of the most abundant of British b.u.t.terflies. Everybody has seen the 'Large White,' though we doubt whether everybody knows that this insect is not of the same species as the two other very common 'Whites.' The three--Large, Small, and Green-veined--are so much alike in general colour and markings, and so similar in their habits and in the selection of their food plants, that the non-entomological, not knowing that insects do not grow in their perfect state, may perhaps regard the larger and the smaller as older and younger members of the same species. But no--they are three distinct species, exhibiting to a careful observer many important marks by which each may be known from the other two.

On Plate I (fig. 3) will be seen a picture of the female _Bra.s.sicae_, in which the following markings are depicted: On each fore wing--a blotch at the tip, a round spot near the centre, another round one nearer the inner margin, and a tapering spot on the inner margin with its point toward the base of the wing. On the hind wings there is only one spot, situated near the middle of the costal margin.

The male may be readily distinguished by the absence of the black markings on the fore wings, with the exception of those at the tips. He is also a trifle smaller than his mate.

This b.u.t.terfly is double-brooded. The first brood appears in April and May, the second in July and August; and the former--the spring brood--which emerges from the chrysalides that have hybernated during the winter, have _grey_ rather than black tips to the front wings.

The ova of _Bra.s.sicae_ may be found on the leaves of cabbages in every kitchen garden, also on the nasturtium, during May and July. They are pretty objects (see fig. 10), something like little bottles or sculptured vases standing on end, and are arranged either singly or in little groups.

As soon as the young larvae are out--from ten to fifteen days after the eggs are deposited--having devoured their sh.e.l.ls, they start feeding on the selfsame spot, and afterwards wander about, dealing out destruction as they go, till little remains of their food plant save the mere stumps and skeletons of the leaves.