Butterflies and Moths Part 18

The chrysalis is a very beautiful object. Its colour is a delicate green, tinged with pink; and the wing-cases project in beautiful curves much beyond the general surface.

_The Pale Clouded Yellow_ (_Colias Hyale_)

The ground colour of this b.u.t.terfly (Plate II, fig. 2) is very variable.

It is usually a sulphury yellow, and on this account the insect is commonly known as the Clouded Brimstone; but sometimes the yellow is exceedingly pale--almost white--and tinged with green.

A very large black blotch, broken by indefinite patches of the ground colour, fills up the tip of each fore wing, and extends to the a.n.a.l angle, becoming narrower as it approaches this point. A black oval spot lies just above the middle of this wing.

The hind wings are bordered with black, and a conspicuous spot of deep yellow lies very near the centre of each.

The antennae are rather short, compared with those of the preceding members of this family, and are distinguished by their reddish-brown colour.

The male and female of this species are similarly marked, but the ground colour of the latter is commonly paler.

This is not by any means a very common b.u.t.terfly with us, though it is very plentiful on the other side of the Channel; but it has a way of taking us by surprise in certain seasons, and then almost neglecting us for several years together.

Its head quarters are certainly the coasts of Kent and Suss.e.x, but it has been taken in considerable numbers as far west as Cornwall, and also to a less extent in some of the midland and northern counties. It is particularly fond of lucerne and clover fields, especially those that are situated close to the sea cliffs; and often it may be seen flying over the beach, sometimes even flitting over the breakers away from land till at last it disappears in the distance. This maritime tendency of _Hyale_ makes it probable that a large number of those that are seen on our south-east coasts have made a pa.s.sage across the narrow end of the Channel.

The eggs are laid in spring, by females that have hybernated throughout the winter, on various leguminous plants, including the lucerne (_Medicago sativa_), black med.i.c.k (_M. lupulina_), purple and Dutch clovers (_Trifolium pratense_ and _T. repens_), and the bird's-foot trefoil (_Lotus corniculatus_), and on these plants you may search for the larva, though it can scarcely be said that you are likely to find it.

The caterpillar is green, with black dots, and a yellowish stripe on each side. When fully grown it ascends a stem of its food plant and changes to a green chrysalis with yellow stripes.

_Hyale_ is single-brooded in England, although two broods regularly appear on the Continent. In our country the perfect insects emerge during July and August. Many of these die before the approach of winter; but, as we have already observed, some hybernate and deposit their eggs in the following spring.

_The Clouded Yellow_ (_Colias Edusa_)

Not only are this and the last species similarly named, but a glance at the figures will show that they much resemble each other in appearance; and we shall also learn presently that in their habits and life history they have much in common.

The male _Edusa_ is shown on Plate II (fig. 3), and when we compare it with its relative on the opposite side, we are at once struck with the superior richness of the brilliant orange or saffron of the ground colour. The black border of both fore and hind wings is also denser, wider, and more extensive. The whole of the yellow area of the hind wings is dusted more or less with black scales, with the exception of a round central spot of deep orange, corresponding with the orange spots on the hind wings of _Hyale_.

The female, which is shown in the accompanying woodcut, is generally larger than the male, and is further distinguished by the very pale yellow spots that break the black border of both pairs of wings.

[Ill.u.s.tration: FIG. 66.--THE CLOUDED YELLOW--FEMALE.]

_Edusa_ further resembles _Hyale_ in the reddish colour of the antennae; and, in both the species, the red legs form a pleasing contrast with the yellow furry surface of the under side of the thorax.

There is a variety of the female of this b.u.t.terfly, in which the ground colour is a _very pale_ yellow, almost white. The hind wings are more thickly dusted with black scales than in the normal insect, and the orange spots of these wings show up much more conspicuously from the contrast with their surroundings.

It is usual to apply distinct names to constant varieties of species--names that are to be added to the ordinary t.i.tle. In this particular case the distinguis.h.i.+ng name is _Helice_, so that we should speak of the variety of _Edusa_ above mentioned as:

_Colias Edusa_, var. _Helice_

Like _Hyale_, _Edusa_ is particularly capricious in its appearance. In certain summers it absolutely swarms in favourite localities, while during the intervals between such remarkable appearances--usually several years--it is positively scarce. The last favoured season was the summer of '92, during which (from the beginning of August to the end of the summer) dozens might easily have been caught in an hour or two; in fact, so plentiful were they in many places, that they were continuously in sight, often several at one time.

Those in search of this insect should repair to the south coast, especially the south-east, and where lucerne and clover fields are in flower. It has very decided maritime tendencies, and may often be seen flying over the cliffs and beaches, and even skipping over the breakers; but, at the same time, it is more or less plentiful in many inland districts. It has been taken in many parts of Ireland and Scotland, particularly along the southern coasts of these countries; but its head quarters are undoubtedly the southern cliffs of England, from Cornwall to Kent, and also the hilly inland districts of the south-eastern counties.

_Edusa_ catching is very lively sport, and is likely to prove sufficient for any lover of outdoor exercise under a scorching sun; for this b.u.t.terfly is not only very powerful on the wing, but its flights are usually long, so that a good run is often absolutely necessary in order to capture it. On very hilly ground, such as _Edusa_ loves, chase is often hopeless, and then it is necessary to resort to stratagem. In such a case the best plan is to make a very cautious approach when the insect has been observed to settle, and then secure it with a sudden down-stroke of the net.

The eggs are laid during May and June by a few females that have survived the winter.

The caterpillar may be found in June and July on its food plants, the chief of which are the bird's-foot trefoil (_Lotus corniculatus_), and the purple and Dutch clovers (_Trifolium pratense_ and _T. repens_). Its colour is gra.s.s-green, and it is marked with a narrow whitish stripe on each side, which is broken by the yellow of the spiracles.

The chrysalis is of a pale yellowish green, and is marked with yellow stripes and reddish-brown dots.

_The Brimstone_ (_Gonopteryx Rhamni_)

This, the last member of the present family, is remarkable for the graceful outline of its wings. The costal margins of the fore pair are most beautifully arched, and both pairs are sharply angled on the hind margins. This latter characteristic is quite unique among British b.u.t.terflies, though we shall presently meet with instances of angular projections on hind wings only.

The ground colour of the male (Plate II, fig. 4) is a rich sulphury yellow, with a greenish tinge. That of the female is a very pale greenish yellow. The only conspicuous markings are small saffron spots, one near the centre of each wing. The antennae are red, short, and beautifully curved; but, unlike the two preceding species, the legs are almost white.

The eggs of this b.u.t.terfly are laid in April on the two species of buckthorn (_Rhamnus catharticus_ and _R. Frangula_) by the females that have successfully weathered the winter. They are of a bright yellow colour, and are usually hatched in about a fortnight.

The body of the caterpillar is green, and it is thickly covered with little black wart-like projections. A pale stripe also runs along each side. During May and June it may be found on its food plants, and toward the end of the latter month it attaches itself by a silken carpet and belt to the under side of one of the leaves.

The chrysalis is of a very peculiar shape, the body being curved, and the wing cases standing out prominently beyond the general surface. Its colour is a bright apple green marked with yellow, and it is so transparent that certain of the structures can be seen through its skin.

The perfect insect emerges in about three weeks after the change to the chrysalis; and may be looked for from July to the end of the summer.

This period may be regarded as the best time in which to hunt for _Rhamni_, but it is to be noted that this b.u.t.terfly makes its appearance during all months of the year, even though it is single-brooded.

A large number seem to hybernate, and their winter sleep is so light that the welcome rays of the sun on a mild day, even during the bleak months of November to February, will often call them out from their hiding places. Then, as a rule, the hybernating b.u.t.terflies do not live long after depositing their eggs for the future brood; but the Brimstone often lives on till its offspring have themselves attained the perfect state, so that it is possible to capture the insects of two different years both on the same day. In such a case it is generally easy to distinguish between the two, for the newly emerged specimens are beautifully bright and fresh in colour, while those of the previous year are more or less faded and worn, their wings being often semi-transparent through the loss of scales, and frequently disfigured by the stains of mildew.

CHAPTER XIII

_THE FRITILLARIES, VANESSAS, AND THE PURPLE EMPEROR_

Family--NYMPHALIDae

We now come to a rather large family, which contains some of our largest and most brilliant b.u.t.terflies. Some of them display the most gaudy colours, and others exhibit patches of a beautiful metallic l.u.s.tre.

If you were to see all the members of this family side by side, they might strike you as being so varied in their appearance that you would wonder why they are all placed in one family group. But, were you to see, in addition to the perfect insects, all their larvae and chrysalides, the reason would be made clear at once, for these earlier stages are seen to resemble each other in certain points at the very first glance. The former are all provided with peculiar spines, and the latter are all more or less angular, and are all suspended to a silken carpet by means of hooks at the tip of the abdomen, and have no belt as we have observed in the case of the _Pieridae_.

The perfect insects, too, although so varied in colouring, are alike in that they have only four walking legs, the first pair being so imperfectly developed as to be useless for this purpose.

This family includes the Fritillaries and the Vanessas.

_The Small Pearl-bordered Fritillary_ (_Argynnis Selene_)

The interesting group of b.u.t.terflies known as the Fritillaries vary considerably in size, but are remarkably uniform in the ground colour of the wings, which, in all cases, is a rich golden or sienna brown; and this ground is chequered with darker colours in such a manner as to remind one of the petals of the wild flower known as the Snake's Head or Fritillary--hence the popular name of the group.