210 HEMIPTERA. 



published accounts of the occurrence of these insects in the 

 Middle, Southern, and Western States, where, at regular in- 

 tervals of seventeen years, varying according to the locality, 

 they are seen even in greater abundance than in Massachu- 

 setts. The following dates and places of their ascent are 

 given in Professor Potter's " Notes on the Locusta decem 

 Septima " ( Cicada septendecim) : Maryland, 1749, 1766, 

 1783, 1800, 1817, 1834 ; South Carolina and Georgia, 1817, 

 1834 ; Middlesex County, New Jersey, 1826 ; Louisiana, 

 1829 ; Gallipolis, Ohio, 1821, and Muskingum, 1829 ; west- 

 em parts of Pennsylvania, 1832 ; Fall River, Massachusetts, 

 1834. To these may be added from other sources, Penn- 

 sylvania, 1715, 1766, 1783, 1800, 1817 ; * Marietta, Ohio, 

 1795, 1812 ; Plymouth, 1633, 1804 ; Sandwich, 1787, 1804, 

 1821 ; Hadley, 1818 ; Westfield, 1835 ; North Haven, Conn., 

 1724, 1741, 1758, 1792, 1809, 1826, 1843; Genesee Coun- 

 ty, New York, 1832; Martha's Vineyard, 1833. From 

 information derived from various sources it appears that this 

 species is widely spread over the country, with the exception 

 only of the northern parts of New England ; and that it 

 may be seen in some portion of the United States almost 

 every year ; and, although certain disturbing causes may 

 occasionally accelerate or retard the return of individuals, 

 or even of an entire swarm, in any one place, yet the lineal 

 descendants of one particular family or swarm will ordina- 

 rily come forth only once in seventeen years, while those 

 of other swarms may appear, after equally regular intervals, 

 in the intervening period, in other places. 



of Baltimore. This last work is exclusively devoted to the history of this insect, 

 and has afforded me much valuable information. From these various sources I 

 have selected the principal facts which follow. Mr. Collins's " Observations on 

 the Cicada of North America," published in the " Philosophical Transactions" of 

 London, Vol. LIV. p. 65, with a plate, probably refer to the seventeen-year Cica- 

 da, but the insects figured are not the same, and seem to be the Cicada pruinosa 

 of Mr. Say. 



A writer in the " United States Gazette " records the appearance of these 

 insects in great numbers in Germantown, Pennsylvania, on the Zbth of May, at 

 four successive periods. 



