GENKIiAI. I!AN(iK OK SI'KCIKS AND KACKS. 
37 
Transition /oiuv 'V]\c ox (Mlnppin^^ of the two I'accs, discussed else- 
where, is well illiist i';i1(m1 hy llie-^e Iwo maps. 
The rani^(^ of (lie ilidi\idil;d broods is mulonhtedly iniieli LTi'ealei- 
than th(^ limits now assi^iuMl. since tli(> i(>coi'(ls until recent \ears 
have l)(>en lai-*x<'ly l>ased on notal)le and d(Mise swai'ins and liaxc 
rarely takcMi into account t li(> scat terini^- indixiduals. w liicli undoubt- 
edly (*xt(Mi(l ov(M' a nnicli ij:r(>ater t(>ri-itory and usually pass umio- 
ticed. The \(M-y car(d"ul it^cords s(>cur(>d of the hi'oods, includinii: and 
snhse(|U(Mit to 1S!)S, hax'e shown nuich of this seattcM'ini^ occurrence 
beyond th(> d(Mis(M" brood limits, as will b(> s(>en in th(> maps illus- 
trating- th(>se broods. This indicatt^s that tlu^ l)r(>akinLr up of the 
Fig. 3.— Miij) showing (listriljution of the broods of tlic 17-ycar raco. 
Cicada has already gone ninch fartlier than was hitherto snpposed, 
and points to the ultimate disappearance of great hroods as such 
and their replacement as scattering individuals every year. The dis- 
appearance of the great hroods, however, is not to he anticipated 
in the very near future, and may not come ahout for a thousand or 
even several thousand 3^ears. This is shown by the fact that the 
hroods 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 mnnlxMs and make just as startling an 
impression as ever. This is due to the fact that much woodland 
remains undisturbed in these ]ocaliti<'s. In other ])laecs. where* tln^ 
woods have been largcdy removed as the result of settlement, the 
Cicada has corresjxmdingly disappeared. 
