184 On the American Locust. 



formed, when he denominated this insect, Cicada Sep- 



tendecim. It is highly probable, however, that the 



periods of the insect's return do vary according to the 

 heat of the climate, and other circumstances. It is rea- 

 sonable to suppose, that the interval is shorter in Geor- 

 gia and Carolina, than in Pennsylvania, New-Jersey, 

 8cc. At what depth have these insects been ob- 

 served in the Peninsula of East- Florida, &c? 



The locusts have been known to make their appear- 

 ance in the city of Philadelphia, in great numbers, 

 penetrating from their long subterranean residence, 

 between the bricks of a pavement. Seventeen years 

 before this occurrence, the spot, now paved, had 

 been an apple-orchard, where the locusts had generated, 

 deposited their eggs, and died. 



Dr. Jones observes that " these insects did not appear 

 to be any way injurious to vegetation." It is, I believe, 

 quite certain, that the Tettigonia, after its resurrection 

 from the ground, eats nothing at all : and, of course, it 

 cannot prove destructive to the vegetation in the man- 

 ner that Gryllus migratorius, and many other insects 

 do. But, the locusts have been known to prove very 

 injurious to vegetation, in many parts of the United- 

 States. 



Even in North-Carolina, these insects have been 

 known to do great injury to the apple- orchards, and to 

 the oak-trees of the forest. So, at least, I have been 

 informed by my friend Alexander Martin, Esq., for- 

 merly Governor of that State. 



