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 ai’e 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 decern 
Septima” ( Cicada geptendechn) : 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- 
ern 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 pruiMt 
of Mr. Say. 
* A writer in the “ United States Gazette ” records the appearance of theso 
insects in great numbers in Germantown, Pennsylvania, on the 2oth of Mat/, at 
four successive periods. 
