BUTTERFLIES AFTER THE WINTER.
THE spring last year was cold and late, but this year looks like being, if not one of the coldest, one of the latest springs on record. March was not a warm month, though there were some wonderful days in the last week, and since April saw March go out like a rather shivering lamb, she has done very little else but shiver herself. It is very seldom that the year turns into the third week in April with hardly a green bud breaking in the hedgerow trees, and with the roof of the woods still the same untouched purple and russet that belong to the windy close of February. The larches have broken out a shimmer of green, but scarcely a bud of the taller trees has moved since the beginning of the month, so slowly is the cold sap running. It will do no harm to plant life, and the owners of orchards are only too thankful when February and March have not brought on the blossom with a rush, to be cut back by late frosts in April, or even in May. But the opening year is a little less bright and interesting
when it is for so long forbidden so much of its warmer grace and colour. For it is not only the trees and flowers, of course, that are backward. The migrant birds have been late in arriving, which would not matter much if they were likely eventually to arrive in the same large numbers. But, un- happily, the rough winds and cold nights have probably killed many of those that were on their way to us. Such light little creatures are easily blown out of their course, and perhaps drown before they can touch land ; and the continued cold checks the supply of the insect food which they hope to find when they arrive, so that many of them in severe weather die actually of hunger.
But some of the brightest features of an English April which the cold weather damps out of the meadow and garden are the early spring butterflies, either those which have passed through the winter hibernating in the form of the perfect insect, or those whose caterpillars or chrysalises have been waiting for warm sunshine, and perhaps warm rain as much as sun, to quicken them to hunger again, or to alchemise the transparence of the chrysalis into pulsing life and painted plumes. Few of the laws which govern the cycle of insect existence are more difficult to understand than those which determine the state in which various species of butterflies shall pass the winter in these islands. Some of the commoner British butterflies, apparently, are never in England in the winter at all, either in the form of eggs, or cater- pillars, or chrysalises, or the perfect insect. The Painted Lady, for instance, which in some years is exceedingly common all over the country (it swarmed over the Southern counties in the autumn of 1904), seems to find the winter too much for it altogether. It appears to be a native of Northern Africa, and to be periodically subject to migration on a vast scale, presumably in search of food, or in order to further in some other way the interests of the species. When, therefore, Painted Ladies swarm in England in Septem- ber, they are either an incursion from abroad, j ust arrived, or they are the progeny of spring arrivals in the country. In either case, the curious point arises that they apparently come to England solely in the interests of those left behind in their native country or dropped on the journey across the Con- tinent. They cannot come to England to propagate their race, for though they may mate and breed in the English summer, the autumn ends their cycle of life, That, probably, is also the case with another common British butterfly, the Red Admiral. Some of the older writers state that the Red Admirals which are seen in late autumn sleep through the 'winter; but that they do so is very doubtful. If they do, they sleep long after the other hibernating butterflies, for it is rare to see a Red Admiral before June, whereas the others will wake up on a warm day even in February. But it would not be strange if the Painted Ladies and Red Admirals differed from their other cousins among the Vanessidae in oversleeping themselves. They are the only two British butterflies which keep late hours, and do not always go to sleep before sunset. Both of them can be found flying about when it is almost too dark to see.
The Red Admiral's relations are thoroughly English, and the problem is to understand why, out of the seven Vanessidem (to use the old-fashioned, intelligible classification) which are to be found in Great Britain, the Red Admiral and Painted Lady alone prefer to spend their winter abroad. The Peacock butterfly, which is on the wing at the same time as the Red Admiral, sleeps through the late autumn and winter ; so do the Large Tortoiseshell and Small Tortoiseshell and the Comma, and so does the largest and most superb of all butter- flies which, though very rare, can fairly be called British. The Camberwell Beauty, or to give it its other names, the White Petticoat, or the Grand Surprise (so called because about 1760 or so it suddenly appeared "in prodigious numbers" throughout the kingdom), is a common enough butterfly on the Continent, but in England there have been perhaps not a hundred caught in the last quarter of a century. But several of those which have been taken have been found hibernating in odd corners, apparently quite satisfied with the temperature. It happened to a schoolboy butterfly-collector in Surrey not long ago to bring in a basketful of logs from the woodhouse, out of which, warmed by the unaccustomed heat of the fire, there presently strutted out on to the carpet a Camberwell Beauty almost as perfect as if it were just out of the chrysalis. Thousands of British entomologists have lived from boyhood to old age and seen such visions in dreams. It would have been a juster fate if an older and more scientific person had been privileged to carry in that firewood ; but not thus do Camberwell Beauties manifest themselves. Next to the Camberwell Beauty as rare hibernators come the Comma and the Large Tortoiseshell, of which the Tortoiseshell seems to have a curious desire for empty houses,—at least, the writer has more than once discovered a Large Tortoiseshell on the window of an uninhabited attic. Peacocks and Small Tortoiseshells are the commonest of the Vanessidae, which in September or October of each year creep into hollow trees, crevices in walls, the interstices of woodstacks, and other dry, convenient places for their winter sleep. Churches are a frequent choice. A year or two ago an old lady saw a Small Tortoiseshell walking down the aisle of a church in January, and wrote to an enter- prising morning paper to chronicle the fact, observing that she had no doubt that it had been hatched from the egg by the heat of the organ. Another hibernating butterfly which only needs a few hours' warmth to send it zigzagging over the flowerless garden is the Brimstone, whose spasmodic appear- ances are also a delight to the news-loving public. Generally it is catalogued, for the benefit of the scientific, as "one of the yellow kind," or "the white kind." The Brimstone, of hibernating butterflies, has an interesting and fascinating peculiarity. When, as often happens on a warm day in April, there are numbers of these butterflies on the wing together, the males will follow one another over a garden bank or hedge through almost exactly the same path in the air. At first it might seem to be the same butterfly "going its round," as the Painted Lady does. But if one of the butterflies is caught, another follows it. Possibly some white-winged lady Brim- stone has flown down the same path, and her yellow-dressed suitors, with their inscrutable antennae, know which way she went.
Of the sixty or seventy butterflies accounted as British, only these six sleep through the winter as winged insects. The others pass through the cold season in the egg stage, or as caterpillars or chrysalises. One at least, the High Brown Fritillary, is said to spend the winter as a fully developed tiny caterpillar, curled up in a still unbroken egg. The cater- pillars of most of the other fritillaries emerge from the egg in the late summer ; nibble for a few days, or even weeks, at the food-plant, in order, so to speak, not to have to sleep on an empty stomach ; and then walk down the stem of the plant, usually the dog-violet, to retire for the winter under a web, or merely bidden among the roots. The general rule for butter- flies, indeed, is to spend the winter as a tiny caterpillar, and then wake up and eat voraciously in the spring. But a few sleep through the snow and frost ready to emerge from the chrysalis on the earliest possible occasion in April or May. The two Cabbage Whites, large and small, hang their grey and green black-peppered chrysalises under convenient ledges of fences and outhouses, and a week's really warm weather sends them chasing one another about the kitchen-garden. The Green-veined White has more delicate tastes, and prefers the flower-border. But these are not the prettiest of April butterflies. In a warm season the Orange Tip, daintiest almost of all, may be flying over the white wood anemones, and perhaps in sunny clearings the little Pearl-bordered Fritillary will be opening and shutting its silver-lighted wings. The third of the pretty April trio, and the most fairy-like, is the Holly Blue, with its underwings of moon- light, and the fascinating indolence of its flight. But the Holly Blues will wait until the north wind has gone. When once they come dancing down into the garden over the ivy and their own sunlit holly, the warmer weather will be here.
Previous page
