The ground colour of the caterpillar is bluish green. It has a narrow yellow stripe down the middle of the back, and two similar but wider stripes along the sides; and the surface of the body is rendered somewhat rough by a number of small black warty projections, from each of which arises a short hair.
When fully grown, it creeps to some neighbouring wall or fence, up which it climbs till it reaches a sheltering ledge. Here it constructs its web and silken cord as already described (page 36), and then changes to a bluish-white chrysalis, dotted with black. The b.u.t.terflies of the summer brood emerge shortly after, but the chrysalides of the next brood hybernate till the following spring.
It is remarkable that we are so plagued with "Whites" seeing that they have so many enemies. Many of the insect-feeding birds commit fearful havoc among their larvae, and often chase the perfect insects on the wing, but perhaps their greatest enemy is the ichneumon fly.
Look under the ledges of a wall of any kitchen garden, and you will see little cl.u.s.ters of oval bodies of a bright yellow colour. Most gardeners know that these are in some way or other connected with the caterpillars that do so much damage to their vegetables. They are often considered to be eggs laid by the larvae, and are consequently killed out of pure revenge, or with a desire to save the crops from the future marauders.
No greater mistake could be made. These yellow bodies are the silken coc.o.o.ns of the caterpillar"s own foes. They contain the pupae of the little flies whose larvae have lived within the body of an unfortunate grub, and, having flourished to perfection at the expense of their host, left its almost empty and nearly lifeless carcase to die and drop to the ground just at the time when it ought to be working out its final changes. Often you may see the dying grub beside the cl.u.s.ter of coc.o.o.ns just constructed by its deadly enemies. Should you wish to test the extent of the destructive work of these busy flies, go into your garden and collect a number of larvae, and endeavour to rear them under cover.
The probability is that only a small proportion will ever reach the final state, the others having been fatally "stung" before you took them.
_The Small White_ (_P. Rapae_)
This b.u.t.terfly closely resembles the last species except in point of size. The male, represented on Plate I (fig. 4), has a dark grey blotch at the tip of each fore wing, a round spot of the same colour beyond the centre of that wing, and another on the costal margin of the hind wing.
The female may be distinguished by an additional spot near the a.n.a.l angle of the fore wing.
Although this and the two other common b.u.t.terflies (_Bra.s.sicae_ and _Napi_) that frequent our kitchen gardens are usually spoken of as "Whites," a glance at a few specimens will show that they are not really white at all, but exhibit delicate shades of cream and yellow, inclining sometimes to buff. The under surfaces are particularly noticeable in this respect, for here the hind wings and the tips of the fore wings display a very rich yellow.
The species we are now considering is also very variable both in its ground colour and the markings of the wings. The former is in some cases a really brilliant yellow; and the latter are in some cases entirely wanting.
_Rapae_ is double-brooded, the first brood appearing in April and May, and the other in July and August.
During these months the eggs may be seen in plenty on its numerous food plants, which include the cabbages and horse-radish of our gardens, also water-cress (_Nasturtium officinale_), rape (_Bra.s.sica Napus_), wild mustard (_B. Sinapis_), wild mignonette (_Reseda lutea_), and nasturtium (_Tropaeolum majus_).
The eggs are conical in form--something like a sugar loaf, with ridges running from apex to base, and very delicate lines from ridge to ridge transversely.
The young larvae often make their first meal of the sh.e.l.l, and then attack the food plant so voraciously that they are fully grown in about three or four weeks. In colour they are of a beautiful glaucous green, hardly distinguishable at times from the leaves on which they rest. A yellow stripe runs along the middle of the back, and lines of yellow spots adorn the sides; and the whole body is covered with very short hairs, each one arising from a minute warty projection.
The pupae may be found during the same seasons and in the same situations as those of _Bra.s.sicae_. They are very variable in colour. Some are of a very pale grey or putty colour, some are decidedly brown, and others of a greenish tinge; and they are often spotted and striped with dark grey or black.
_The Green-veined White_ (_P. Napi_)
A non-observant beginner at entomological work may easily mistake this insect for the last species, for the ground colour and markings are very similar, even to the features by which the s.e.xes are distinguished from each other; but an inspection of the under surface will give a ready means of identification, for here the wing rays are bordered with black scales which, by contrast with the rich yellow around them, often appear of a greenish hue. The b.u.t.terfly receives its popular name from this circ.u.mstance.
A careful observer, however, will readily find distinguishing marks on the upper side, for here also the chief "veins" are more or less accompanied with black scales, especially the extremities of those of the fore wings, where little triangular blotches are often distinctly formed; and the dark veining of the under surface of the hind wings frequently shows through. The under side of this insect is shown on Plate I (fig. 5).
This b.u.t.terfly is not so abundant as the two preceding, but is widely distributed throughout England, and is in most parts decidedly plentiful.
The first brood (for it also is double-brooded) appears during April and May, and the second in July and August.
The eggs are very similar to those of _Rapae_, resembling ribbed and striated sugar loaves; and the larvae are of the same rich glaucous green, but may be identified by the black spiracles surrounded by yellow rings. In our gardens we may find both eggs and larvae on mignonette and horse-radish; the other food plants of this species include the water-cress (_Nasturtium officinale_), winter cress (_Barbarea vulgaris_), rape (_Bra.s.sica Napus_), cuckoo-flower (_Cardamine pratensis_), and Jack-by-the-hedge (_Sisymbrium Alliaria_).
The pupa is greenish, and marked with small black dots.
_The Bath or Green-chequered White_ (_P. Daplidice_)
There is no doubt that many b.u.t.terflies migrate from one country to another across the seas; and as the Bath White is very common on the other side of the Channel, and has been taken very sparingly in England almost exclusively in the south-east, it is highly probable that the majority of those that have been captured here are specimens that have taken a voluntary trip across the water, or have been blown over during rough weather.
This b.u.t.terfly is one of our greatest rarities, and the capture of a specimen in England is an event that must necessarily be recorded in our entomological literature. It seems that _Daplidice_ has bred in England, for its caterpillars have been found at large on one or two occasions, so I will give a short description of the various stages of the insect, with a hope that some of my readers may be fortunate enough to meet with it.
The female b.u.t.terfly is shown on Plate I, fig. 6. From this it will be observed that each of the fore wings is tipped with a rather large smoky-black blotch, in which are four white spots. A double spot of the same colour also occupies a place near the centre of the wing, and another smaller and round one lies near the a.n.a.l angle. The hind wings are clouded with grey, and bordered along the hind margin with distinct smoky-black spots.
The male may be distinguished from the female by the absence of the spot near the a.n.a.l angle of the fore wings, and of all the clouds and spots of the hind wings. Nevertheless the latter have a decidedly clouded appearance, but this is due to the markings of the under surface showing through them.
The under side of both s.e.xes is most beautifully marked--the fore wings resembling the upper sides, but the hind pair chequered with a beautiful soft green on a pale yellow ground.
The eggs of this insect are deposited during April and May, and again in August or September--for it is, like the other "Whites,"
double-brooded--on two species of Wild Mignonette (_Reseda lutea_ and _R. luteola_).
[Ill.u.s.tration: FIG. 65.--THE BATH WHITE--UNDER SIDE.]
The caterpillars, which are of a bluish colour, with two yellow stripes down the back, and two others along the sides, may be _looked_ for in June and September. Those of the first brood only have been taken in this country, while the others on the Continent change to the chrysalis in the autumn, and hybernate in this state throughout the winter.
The chrysalis is of a brownish colour, and closely resembles that of the Small White in form.
Those in search of this rare British insect should wander along the south-east coast, and net all the doubtful slow-flying small Whites (_Daplidice_ is rather slow and heavy on the wing), and their perseverance _may_ be rewarded with a prize that will ever be a reminder of a glorious catch and an eventful day. If you fail in this, and most probably you will, rather than remain a stranger to this beautiful and interesting insect, fill up the blank in your cabinet with a foreign specimen, which can be obtained at any time for a few pence, but be careful to label it "not British," in order that your brother collectors may not be deceived, or be led to make any unnecessary inquiries.
_The Orange Tip_ (_Euchloe Cardamines_)
No one could possibly mistake the male of this species for any other British b.u.t.terfly, the popular name alone giving quite sufficient information for its identification, but the female Orange Tip is _not_ tipped with orange, and its markings, both above and beneath, resemble those of _Daplidice_ so nearly that the same written description might apply almost equally well to both.
On Plate I (fig. 7) is shown the upper side of the male, and just opposite it (fig. 8) the under surface of the same. The female is usually a little larger than her mate, and is marked similarly on both sides except that the bright orange blotch is entirely wanting. She may always be distinguished from _Daplidice_ by the smaller size of the white spots that break the dark blotch at the tip of the fore wing; also by the very small size of the dark spot in the centre of the same wing.
The green chequerings of the under side of the hind wings are also more sharply defined, and the insect is generally of a lighter build.
Like many other b.u.t.terflies, the Orange Tip is subject to variations in colouring. Sometimes a pale but bright yellow takes the place of the white ground, and the orange blotch of the male is occasionally present on the upper or lower surface only.
_Cardamines_ is a single-brooded insect, and is essentially a creature of the spring, at which time it may be found in abundance in lanes, meadows, and clearings in woods throughout the British Isles. Its flight is so light and airy that even the female may easily be distinguished from other Whites when on the wing, while the brilliant orange of the male, intensified by the bright rays of the spring sun, may be identified at some considerable distance.
The food plants of _Cardamines_ include the cuckoo-flower (_Cardamine pratensis_) and the bitter cress (_C. impatiens_), after which the insect is named, also water-cress (_Nasturtium officinale_), winter cress (_Barbarea vulgaris_), rock cress (_Arabis perfoliata_), hedge mustard (_Sisymbrium officinale_), Jack-by-the-hedge (_S. Alliaria_), wild mustard (_Bra.s.sica Sinapis_), &c., and the eggs of the b.u.t.terfly may be found on these during May and June.
The caterpillar (Plate VIII, fig. 2) is green, with a white stripe on each side, and its body is covered with short hair. In July it is fully grown, and ascends a stem of the food plant to prepare itself for its long winter sleep.
The chrysalis (Plate VIII, fig. 8) is a very peculiar object. Both ends are much elongated and sharply pointed; and the foremost extremity stands out at an angle with the stem to which it is attached.
This b.u.t.terfly should be looked for during April and May, but in mild seasons it may often be met with in March.
_The Wood White_ (_Leucophasia Sinapis_)
The distinguishing feature of this b.u.t.terfly (see Plate II, fig. 1) is the extreme lightness and delicacy of its build. Its wings are narrow, and rounded at the tips; and the only mark to relieve the white ground of the upper side is a squarish blotch at the tip of the fore wing, and even this is either very indistinct or entirely absent in the female.
The under surface is clouded with a pale greenish tint.
This insect may be looked for in May and again in August, in paths and clearings in woods, where it moves along with a slow but steady flight, hardly ever seeming to rest for a moment. It is not by any means a common b.u.t.terfly, but is very widely distributed, and sometimes appears in considerable numbers in certain favoured spots. Among the localities recorded may be mentioned Torquay, Exeter, Plymouth, South Dorset, New Forest, Reading, Darent Woods, Morecambe Bay, Haslemere, Windermere, &c.
The caterpillar is of a beautiful green colour, and is covered with short whitish hairs. A darker green stripe runs down the middle of the back, and a bright yellow stripe along each side. Its food plants are the tufted vetch (_Vicia Cracca_), bird"s-foot trefoil (_Lotus corniculatus_ and _L. pilosus_), bitter vetch (_Lathyrus tuberosus_), and the everlasting pea (_L. sylvestris_).