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قراءة كتاب British Butterflies: Figures and Descriptions of Every Native Species

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British Butterflies: Figures and Descriptions of Every Native Species

British Butterflies: Figures and Descriptions of Every Native Species

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دار النشر: Project Gutenberg
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it are common to some other insects besides butterflies. Moths and hawk-moths have mealy wings, and are often gaily coloured too; whilst, on the other hand, some butterflies are as dusky and plain as possible. Thus the crimson-winged Tiger, and Cinnabar moths get the name of butterflies, and the Meadow brown butterfly is as sure to be called a moth. So, as neither colouring nor mealy wings furnish us with the required definition, we must find some concise combination of characters that will answer the purpose. Butterflies, then, are insects with mealy wings, and whose horns (called "antennæ") have a clubbed or thickened tip, giving them more or less resemblance to a drum-stick. So the difference in the shape of the antennæ is the chief outward mark of distinction between butterflies and moths, the latter having antennæ of various shapes, threadlike or featherlike, but never clubbed at the tip.

Having thus settled how a butterfly is to be recognized at sight, let us see what butterfly life is: how the creature lives, and has lived, in the stages preceding its present airy form.

I.

In like manner with other insects, all butterflies commence their existence enclosed in minute eggs; and these eggs, as if shadowing forth the beauty yet undeveloped whose germ they contain, are themselves such curiously beautiful objects, that they must not be passed over without admiring notice. It seems, indeed, as if nature determined that the ornamental character of the butterfly should commence with its earliest stage; form, and not colour, being employed in its decoration, sculpture being here made the forerunner of painting.

Some of these forms are roughly shown on Plate II. (figs. 1-7), but highly magnified; for as these eggs are really very tiny structures, such as would fall easily through a pin-hole, the aid of a microscope is of course necessary to render visible the delicate sculpture that adorns their surface. The egg (fig. 1, Plate II.) of the common Garden white butterfly (Pieris Brassicæ) is among the most graceful and interesting of these forms, and also the most easily obtained. It reminds us of some antique vessel, ribbed and fluted with consummate elegance and regularity.

Others—such as those of the Large Heath butterfly (fig. 3), and the Queen of Spain Fritillary (fig. 2), simulate curious wicker-work baskets. The Peacock butterfly has an egg like a polygonal jar (fig. 4), while that of its near ally, the large Tortoise-shell (fig. 5), is simply pear-shaped, with the surface unsculptured and smooth

(fig. 5). The eggs of the Meadow Brown (fig. 6), and the Wood Argus (fig. 7), are globular—the former with lines on its surface like the meridian lines on a geographical globe, and a pretty scalloping at the top that gives a flower-like appearance to that portion; the latter has the whole surface honey-combed with a network of hexagonal cells. Such are a few of the devices that ornament the earliest cradle of the butterfly; but probably those of every species would well repay their examination to any one who possesses a microscope.

Prompted by a most remarkable instinct, and one that could not have originated in any experience of personal advantage, the female butterfly, when seeking a depository for her eggs, selects with unerring certainty the very plant which, of all others, is best fitted for the support of her offspring, who, when hatched, find themselves surrounded with an abundant store of their proper food.

Many a young botanist would be puzzled at first sight to tell a sloe-bush from a buckthorn-bush. Not so, however, with our Brimstone butterfly: passing by all the juicy hedge-plants, which look quite as suitable, one would think, she, with botanical acumen, fixes upon the buckthorn; either the common one, or, if that is not at hand, upon another species of rhamnus—the berry-bearing alder—which, though a very different looking plant, is of the same genus, and shares the same properties. She evidently works out the natural system of botany, and might have been a pupil of Jussieu, had she not been tutored by a far higher Authority.

II.

This display of instinct would seem far less wonderful did the mother butterfly herself feed on the plant she commits her eggs to. In that case, her choice might have appeared as the result of personal experience of some peculiar benefit or pleasure derived from the plant, and then this sentiment might have become hereditary; just as, for example, the acquired taste for game is hereditary with sporting dogs. Whereas the fact is, that a butterfly only occasionally, and as a matter of accident rather than rule, derives her own nectareous food from the flowers of the plant, whose leaves nourish her caterpillar progeny. So that this, as well as numberless other phenomena of instinct, remains a mystery to be admired, but not explained by any ordinary rule of cause and effect.

Having thus efficiently provided, as far as board and lodging are concerned, for the welfare of the future brood, the mother seems to consider them settled for life, takes no further care of them, nor even awaits the opening of the sculptured caskets that contain their tiny life-germs; but, trusting them to the sun's warmth for their hatching, and then to their own hungry little instincts to teach them good use of the food placed within their reach, she sees them no more.

But though abandoning her offspring to fate in this manner, it must not be imagined that the butterfly mother takes her pattern of maternity from certain

human mothers, and in a round of "butterfly's balls," and such like dissipations, forgets the sacred claims of the nursery. No, she has far other and better excuses for absenting herself from her family; one of which is, that she usually dies before the latter are hatched; and if that is not enough, that the young can get on quite as well without her; for probably she could not teach them much about caterpillar economics, unless, indeed, she remembered her own infantile habits of lang syne, so totally different from those of her perfected butterfly life.

The space of time passed in the egg state varies much according to the temperature—from a few days when laid in genial summer weather, to several months in the case of those laid in the autumn, and which remain quiescent during the winter, to hatch out in the spring.

The eggs of butterflies, in common with those of insects in general, are capable of resisting not only vicissitudes, but extremes of temperature that would be surely destructive of life in most other forms. The severest cold of an English winter will not kill the tender butterfly eggs, whose small internal spark of vitality is enough to keep them from freezing under a much greater degree of cold than they are ever subjected to in a state of nature. For example, they have been placed in an artificial freezing mixture, which

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