14 THE PKHIODICAL CICADA. 
iiii\)riiiod that very few ul" the insects appeared that year. In 
exphination of this he writes: ''The woodland in the A'icinity has 
been steadily reduced and the cicadas, of which there are records 
going back about a centur}^, seem to be djdng out. The owner of the 
land where the cicadas appeared (a man born in 1815, died in 1892) 
informed me that the rate of reduction was so rapid tliat he d()u])te(l 
if any of them would appear in 1903." 
To the lover of nature there is something regrettable in tliis slow 
extermination of an insect which presents, as does the periodical 
Cicada, so much that is interesting and anomalous in its ha])its and 
life liistory. During the long periods of past time the s])ecies has 
recurred with absolute regularity except as influenced b}^ notable 
changes in the natural topograpliical conditions and the despoliation 
of forests which has followed the path of settlement b}^ the white man. 
It is interesting, therefore, in thought to trace the liistory of this 
species backward, taking, as time measures, its periodic recurrences, 
until in retrospect it is possible to fancy its shrill notes jarring on the 
ears of the early colonists or listened to in the woodlands bordering 
the ocean by the still earlier discoverers and explorers. Still more 
remote]*^ one can picture its song causing wonderment to the savage 
Indians who attributed to it baleful influences, and 3^et) less dainty 
than their white followers^' usecl the soft, newly emerged cicadas as 
food; or further back in time, when it had only wild animals as 
auditors. With these long-time measures our brief periods of days, 
weeks, months, and 3^ears seem trivial enough. 
THE RACES, BROODS, AND VARIETIES OF THE CICADA. 
Much obscurity must always attach to the past liistor}' of tliis insect 
and the origin of its peculiar habits, and notably the causes and con- 
ditions which have led to the establislunent of the long underground 
existence and the equally extraordinar}" regularitj' in time of emer- 
gence at the end of this period. Explanations may, however, be sug- 
gested for some of its peculiarities as presented in its life at the j^resent 
time — as, for example, the origin of the two distinct races, one with a 
17-year period and the other with a 13-year period, with ])ot]i of 
wliich a small variety occurs, and the existence of a multitude of (hs- 
tinct broods occujn'ing the same or different territory and appearing 
in different years but with absolute regularity of ])eriods. 
A SEVENTEEN-YEAR RACE AND A THIRTEEN-YEAR RACE. 
One of tlie greatest difficulties in solving tlie pro])lem of the broods 
of this insect and tlieir geographical limits was removed by the dis- 
covery of the existence of two (Hstinct races — namely, one requiring 
seventeen years for its development and limited geograpliically, in a 
