RANGE OF BROODS IN ORDER OF PUTUBE APPEARANCES. 29 
independent position. Brood VIII, however, seems to be closely allied 
to V, and surrounds, in a way, the territory occupied by the latter, and 
also extends eastward to the coast. 
Brood IX, as already stated, is very doubtful, the Colorado locality 
perhaps being due to confusion with some other species, and the other 
records perhaps due to confusion with the 13-year race. 
It will be seen, therefore, that the 17-year race divides itself up into 
related broods as follows: Broods XI and XII: XIII and XI V: X V : 
XA'II; XIX, XX, XXI, XXII, and I: V and VIII, and IX. 
THE RANGE OF THE WELL-ESTABLISHED BROODS, TAKEN IN THE 
ORDER OF FUTURE APPEARANCES. 
In the following description of the broods, they are taken up in the 
chronological order of their appearance as indicated by the table given 
Fig. 4. — Map showing distribution of Broods XVTI and \ "II. Lfi - 
on page 23. Many of the maps which accompany the descriptions 
include both a 17-year and a 13-year race: in other words, whenever 
broods of both races occur in the same year they are combined on one 
map. The distribution of the broods of the 17 year race is indicated by 
the black disks and interrogation points, the latter referring to doubt 
ful localities, and of the 13-year race by circles and crosses, the latter 
marking the doubtful records. The 13-year Broods VII and X, recur- 
ring, respectively, in 1911 and 191 1, are not shown on the maps of those 
years, having been already depicted on the maps for 1898 and 1901, 
