HEMIPTERA. 173 



themselves precipitately ; but running to the side of the limb, 

 they deliberately loosen their hold, and fall to the earth, It 

 seems, then, that they are not borne to the ground in the egg state 

 by the limbs in which their nests are contained, but spontaneously 

 make the perilous descent, immediately after they are hatched, 

 without any clue, like that of the canker-worm, to carry them in 

 safety through the air and break the force of their fall. The in- 

 stinct which impels them thus fearlessly to precipitate themselves 

 from the trees, from heights of which they can have formed 

 no conception, without any experience or knowledge of the re- 

 sult of their adventurous leap, is still more remarkable than that 

 which carries the gosling to the water as soon as it is hatched. In 

 those actions, that are the result of foresight, of memory, or of 

 experience, animals are controlled by their own reason, as in those 

 to which they are led by the use of their ordinary senses or by 

 the indulgence of their common appetites they may be said to be 

 governed by the laws of their organization ; but in such as arise 

 from special and extraordinary instincts, we see the most striking 

 proofs of that creative wisdom which has implanted in them an 

 unerring guide, where reason, the senses, and the appetites would 

 fail to direct them. The manner of the young cicadas' descent, 

 so different from that of other insects, and seeming to require a 

 special instinct to this end, would be considered incredible per- 

 haps, if it had not been ascertained and repeatedly confirmed by 

 persons who have witnessed the proceeding. On reaching the 

 ground the insects immediately bury themselves in the soil, bur- 

 rowing by means of their broad and strong fore-feet, which, like 

 those of the mole, are admirably adapted for digging. In their 

 descent into the earth they seem to follow the roots of plants, and 

 are subsequently found attached to those which are most tender 

 and succulent, perforating them with their beaks, and thus imbib- 

 ing the vegetable juices which constitute their sole nourishment. 

 They do not appear ordinarily to descend very deeply into the 

 ground, but remain where roots are most abundant ; and it is 

 probable that the accounts of their having been discovered ten or 

 twelve feet from the top of the ground have been founded on 

 some mistake, or the occurrence of the insects at such a depth 

 may have been the result of accident. The only alteration to 



