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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    cess. It is accelerated by heat, and retarded by a low temperature. Those we held in our hands hatched sooner than those on the limbs at the temperature of the air. The act of delivery differs but little from that of the chrysalis. A rupture of the fetal membrane cover- ing the back is first effected by muscular motion. The insect draws its body upwards, and seems to swell, whilst it throws its lower extremities to and fro, labouring in all possible attitudes to extricate itself. It draws out its head slowly, disengages its fore legs, and in a few minutes its whole body. The moment it is set at liberty it begins to caper as if it were in a new state of existence, seeming to exult in its delivery. For a moment it seems to be at a loss what to do, till instinct begins to operate and directs it to its proper element. As soon as it is freed from its shell it falls to the ground. It does not run nor creep down the body of the tree, nor cast itself off precipitately; but runs to the side of the limb, loosens its claws, and falls to the ground by an instinctive rule, for from whatsoever height it may have descended, it sustains no inju- ry. When it inters itself it descends by the side of some vegeta- ble root, which is its first and only aliment under ground. In this state it is blind, and acts by the sense of touch, and feels its way downward by its antennae. Although its eyes are promi- nent, they are covered by an opaque film, through which the rays of light cannot pass. What would be the use of vision to an in- sect destined to dwell in darkness sixteen years and nine months ? Perfectly formed eyes would be an incumbrance, while the mem- brane that invests them defends them from injuries in passing through a grass-irritating medium. In this state the young insect shews, also, the rudiments of wings, but they are not unfolded, because they are not wanted. What would be their use when adult age, the only time they could use them, is almost as distant as that of a child born at the same time ? While it has fit for use all the parts required beneath the soil, it is restrained in the use of others till it shall have passed through a long infancy, a short ado- lescence, and puts on the toga virilis at seventeen.