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British Butterflies. William S. Coleman
Читать онлайн.Название British Butterflies
Год выпуска 0
isbn 4064066452827
Автор произведения William S. Coleman
Жанр Математика
Издательство Bookwire
Every one looking at a butterfly must have remarked its long horns, called antennæ,[4] which project from above the eyes, like jointed threads, thickening—in some species gradually, in others suddenly—into a club or knob at the extremity; a peculiarity which, it will be remembered, was pointed out at the commencement, as a prominent mark of distinction between butterflies and moths.
Very graceful appendages are these waving antennæ, and evidently of high importance to their owner; but still, their exact office or function is unknown, notwithstanding that many guesses and experiments have been made with a view of settling that question.
Investigators have perhaps erred, by assuming at the outset that these antennæ must be organs of some sense that we ourselves possess; whereas, I think that there is much evidence to show that insects are gifted with a certain subtle sense, for which we have no name, and of which we can have as little real idea, as we could have had of the faculty of sight, had all the world been born blind.
For example; if you breed from the chrysalis a female Kentish Glory Moth, and then immediately take her—in a closed box, mind—out into her native woods, within a short space of time an actual crowd of male "Glories" come and fasten upon, or hover over, the prison-house of the coveted maiden. Without this magic attraction, you might walk in these same woods for a whole day and not see a single specimen, the Kentish Glory being generally reputed a very rare moth; while as many as some 120 males have been thus decoyed to their capture in a few hours, by the charms of a couple of lady "Glories," shut up in a box.
Now, which of our five senses, I would ask—even if developed into extraordinary acuteness in the insect—would account for such an exhibition of clairvoyance as this?
May not, then, this undiscovered sense, whatever may be its nature, reside in the antennæ? for it is a remarkable fact, that the very moths, such as the Eggers, the Emperor, the Kentish Glory, &c., which display the above-mentioned phenomenon most signally, have the antennæ in the males amplified with numerous spreading branches, so as to present an unusually large sensitive surface. This seems to point to some connexion between those organs and the faculty of discovering the presence, and even the condition, of one of their own race, with more, perhaps, than a mile of distance, and the sides of a wooden box, intervening between themselves and their object.
Whilst writing this, the current number of the "Entomologist's Weekly Intelligencer" has arrived, and I there read that Dr. Clemmens, an American naturalist, has been lately experimenting on the antennæ of some large American moths, for the purpose of gaining some information as to their function. The article, though very interesting, is too long for quotation here; but it appears that with the moths in question, a deprivation of the whole, or even part of the antennæ, interferes with, or entirely annihilates the power of flight, so that the creature when thus shorn, but not otherwise injured, if thrown into the air seems to have no idea of using his wings properly, but with a purposeless flutter tumbles headlong to the earth. Still this merely goes to prove that the antennæ are the instruments of some important sense, one of whose uses is to guide the creature's flight; but as many wingless insects have large antennæ, this evidently is not their only function.
The antennæ are also often styled the "feelers;" but with our present incomplete knowledge of their nature, the former term is preferable, as it does not attempt to define their use as the word "feelers" does.
Considerable variety of form exists in the clubbed tip of the antennæ in various butterflies, as will be seen by reference to Plate II., where three of the most distinct forms are shown considerably magnified. Fig. 12 is the upper part of the antenna of the High-brown Fritillary (Argynnis Adippe), the end suddenly swelling into a distinct knob. Fig. 13 is that of the Swallow-tail Butterfly (Papilio Machaon), the enlargement here being more gradual; and fig. 14 is that of the Large Skipper Butterfly (Pamphila Sylvanus), distinguished by the curved point that surmounts the club. These differences in the forms of the antennæ are found to be excellent aids in the classification of butterflies, and I shall therefore have occasion to refer to them more minutely in describing the insects in detail.
The stems of these organs are found to be tubular, and at the point of junction with the head the base is spread out (as shown at fig. 15), forming what engineers call a "flange," to afford sufficient support for the long column above.
The legs are the last portions of the butterfly framework that require especial notice, on account of a peculiar variation they are subject to in different family groups.
It may be laid down as an axiom, that all true insects have six legs, in one shape or another; and butterflies, being insects, are obedient to the same universal rule, and duly grow their half-dozen legs; but in certain tribes the front pair, for no apparent reason, are so short and imperfect as to be totally useless for walking purposes, though they may possibly be used as hands for polishing up the proboscis, &c. So the butterfly in this case appears, to a hasty observer, to have only four legs.
This peculiarity is a constant feature in several natural groups of butterflies, and therefore, in conjunction with other marks, such as the veining of the wings and the shape of the antennæ, its presence or absence is a most useful mark of distinction, in classifying or searching out the name and systematic place of a butterfly.
Footnotes
2
Making
Lepidos
in genitive.
3
A word derived from the Latin, and meaning literally a "sucker."
4
Antenna
in the singular number.
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