24 



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 litlle 

 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 antennas. 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. 



