16 THE PERIODICAL CICADA. 
nonpublication of Doctor Smith’s monograph,” these broods would 
have failed ot the abundant proof on which they now rest. The race 
name of tredecim for the 13-year broods was suggested by Walsh and 
Riley without knowledge of its earlier use by Doctor Phares. The 
latter’s early articles inthe Republican are lost altogether, the author 
himself not being able to recover them in later years, and the credit 
for the name tredecim for the 13-year race, following the customary 
rules, should go to Walsh and Riley. 
The discovery of the 13-year Southern race was of vast assistance 
in clearing up the confusion which had attended the study of the 
different broods of this insect and enabled Walsh and Riley to sepa- 
rate some sixteen distinct broods, three of which belong to the tre- 
decim race, and later enabled Professor Riley, with the aid of Doctor 
Smith’s paper, to increase the number of tredecum broods to seven 
and the total of the broods to twenty-two, twenty-one of which the 
records of subsequent appearances have proved to be valid. 
Doctor Smith’s remarks in his manuscript chapter on geographical 
tribes and districts present the status of the 17-year and 13-year 
races very clearly. He says: 
There are two divisions or tribes, differing from each other only in the periods of 
their lives; the one and much the larger division living 17 years, and the other 
13; hence the impropriety of the specific name septendecim. * * * The anatomy 
of the insects of both divisions is precisely the same, but septendecim does not of 
course apply to the Southern division, whose lives are but 13 years. Shall we call 
the latter Cicada tredecim? Why there is this difference in the periods of lives of the 
two tribes we can not explain. It is not the climate that causes it, as a moment’s 
reflection will prove. If that were the cause the difference would be more gradual. 
For example, in northern New York they would have been, say, 17 years; in Pennsyl- 
vania, 16; in Maryland and Virginia, 15; in North Carolina and Tennessee, 14, and 
in South Carolina, etc., 13 years in completing their existence. But that is not the 
case. The difference of years takes place abruptly on and about the line of 34° 
and 35° of north latitude, on the north side of which the period is 17 years and on 
the south 13 years. 
While Doctor Smith is hardly justified in the last statement, it is 
nevertheless true that the 17-year race is northern and the 13-year 
race is southern. The territory of the two races is graphically shown 
in figures 2 and 3, and is described in detail and mapped for all the 
broods in a later section. 
In this bulletin the two forms of the periodical Cicada have been 
designated as ‘‘races,”’ adopting the position taken by Professor Riley 
and the majority of the writers on this insect, rather than consider- 
ing them to be distinct species, as is held by some specialists. Pro- 
fessor Riley and others opposed the idea of their being specifically 
distinct, not only because of their practical identity in general char- 
aA summary, with extracts, of this manuscript made by Professor Riley is the 
writer’s source of information on this valuable paper, which, while containing much 
error and wrong inference, yet indicates careful study and accurate observation, 
