GENERAL RANGE OF SPECIES AND RACES, 5) 
Transition zone. The overlapping of the two races, discussed else- 
where, is well illustrated by these two maps. 
The range of the individual broods is undoubtedly much greater 
than the limits now assigned, since the records until recent years 
have been largely based on notable and dense swarms and have 
rarely taken into account the scattering individuals, which undoubt- 
edly extend over a much greater territory and usually pass unno- 
ticed. The very careful records secured of the broods, including and 
subsequent to 1898, have shown much of: this scattering occurrence 
beyond the denser brood limits, as will be seen in the maps illus- 
trating these broods. This indicates that the breaking up of the 
HAMPS! 
B Wiw 
= 
o 
“) 
Oo 
7) 
v 
v 
Fig. 3.—Map showing distribution of the broods of the 17-year race. 
Cicada has already gone much farther than was hitherto supposed, 
and points to the ultimate disappearance of great broods as such 
and their replacement as scattering individuals every year. The dis- 
appearance of the great broods, however, is not to be anticipated 
in the very near future, and may not come about for a thousand or 
even several thousand years. This is shown by the fact that the 
broods first seen by the early colonists in New England on Cape 
Cod, at Plymouth, and on Marthas Vineyard are, as elsewhere noted, 
still practically unreduced in numbers and make just as startling an 
impression as ever. This is due to the fact that much woodland 
remains undisturbed in these localities. In other places, where the 
woods have been largely removed as the result of settlement, the 
Cicada has correspondingly disappeared. 
