12 THE PERIODICAL CICADA. 
the early colonists or listened to in the woodlands bordering the ocean 
by the still earlier discoverers and explorers. Still more remotely one 
can picture its song causing wonderment to the savage Indians who 
attributed to it baleful influences, and yet, less dainty than their white 
followers, used 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 years 
seem trivial enough. 
THE RACES, BROODS, AND VARIETIES OF THE CICADA. 
Much obscurity must always attach to the past history of this insect 
and the origin of its peculiar habits, and notably the causes and con- 
ditions which have led to the establishment of the long underground 
existence and the equally extraordinary regularity in time of emergence 
at the end of this period. Explanations may, however, be suggested 
for some of its peculiarities as presented in its life at the present 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 both of which a small 
variety occurs, and the existence of a multitude of distinct broods 
occupying the same or different territory and appearing in different 
years but with absolute regularity of periods. 
A SEVENTEEN- YEAR AND A THIRTEEN-YEAR RACE. 
One of the greatest difficulties in solving the problem of the broods 
of this insect and their geographical limits was removed by the dis- 
covery of the existence of two distinct races — namely, one requiring 
seventeen years for its development and limited geographically, in a 
general way, to the northern half of the range of the species, and the 
other requiring but thirteen years for its development and covering 
the southern half of the range of the species. 
This interesting and very important fact was first discovered, it seems, 
by Dr. D. L. Phares, then of Woodville, Miss., who announced the 13-year 
period for the southern broods in a local paper — the Woodville (Miss.) 
Eepublican, May 17, 1815. This paper having only a local circulation, 
the significance of this discovery was lost sight of, and probably never 
came to the attention of naturalists; and it was not until 1868, when 
Dr. B. D. Walsh and Prof. 0. V. Eiley arrived at the same conclusion 
and published in a joint article, in the American Entomologist, 1 a mass 
of accumulated observations bearing thereon, that the 13-year period 
for the Southern broods came to be generally accepted. 
In Professor Eiley's first report on the insects of Missouri, published 
the following year (1869), the joint article just referred to was reproduced 
substantially without change, except for a revision of the classification 
of the broods, based on data obtained chiefly from a very valuable 
