Notes on the Locusta septentrionalis americanae decem septima / by Nathaniel Potter.

  • Potter, Nathaniel, 1770-1843.
Date:
1839
Catalogue details

Licence: Public Domain Mark

Credit: Notes on the Locusta septentrionalis americanae decem septima / by Nathaniel Potter. Source: Wellcome Collection.

Provider: This material has been provided by the National Library of Medicine (U.S.), through the Medical Heritage Library. The original may be consulted at the National Library of Medicine (U.S.)

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    are attached. Probably we have given them more power than they possess, and we think it will be found they cannot see so far. Their capacity for keen vision is vastly increased by the almost incalculable number of lenses, with which the eye is supplied ; and those so convex that objects invisible, unless through a microscope that magnifies a hundred andjijly thousand, is clear to them. With one that magnified four hundred and ninety thousand, we counted the lenses with sufficient accuracy, and after repeated trials, came to the conclusion, that there were ten thousand two hundred, not many more or less. This mechanism gives the power of seeing in all possible directions, and we will presently perceive how important it is to the economy of the insect. We have already alluded to the peculiar mechanism of the in- struments by which the locust imbibes its aliment, so different from those of the cicadae. They are exceedingly minute, and on a su- perficial view, unappropriated; but with a fine glass, their office is designated at once. They seek nourishment that is always present and ready, pre- pared for the instruments through which they are to receive it. The exhalation from vegetable barks forms their entire subsistence. This they probably could not find without exquisitely keen vision, as they have no olfactory nerves, that can be demonstrated. We are, nevertheless, not to infer positively that they can neither hear nor smell. We must search for another apparatus to find the conduit of their nutriment. The antennas, we have re- marked, are bristle shaped, standing between the eyes and the rostrum or beak which furnishes the avenue through which the nourishment is conveyed. It is in this sense only that the locust can be said to have a mouth. There are three exquisitely fine hairs appended to its extreme points, by which, through a high magnify- ing power, we see them distinctly feeding on the dewy exhalation of vegetable barks—a material that may be compared to the in- sensible perspiration of the animal body; the insensible perspiration of the vegetable skin. Although we cannot demonstrate that they are tubular, they probably act by capillary attraction. The exquisite 2