68 
THE PERIODICAL CICADA. 
Brood XX—Tredecim—l90S. (Fig. 23.) 
This is a small brood, founded on records given by Doctor Smith. 
Some of the localities cited were confirmed and others negatived on 
the recurrence of the brood in 1869, as reported by Professor Riley in 
Bulletin No. 8, old series, of the Division of Entomology. Since that 
date tliree doubtful localities have been added, one each for Virginia, 
North Carolina, and Georgia, possibly based on 17-year ])r()ods which 
appeared in conjunction "svith tliis brood. 
Fig. 23. -Map showing distribution of Brood XX, 1908. 
The distribution, by States and counties, is as follows: 
Georgia. — Banks, Greene, Jasper, Muscogee, Walker, Washington. 
North Carolina — Wilkes (?). 
Virginia. — Wise (?). 
Brood XXI— Trededm— 1909. (Fig. 24.) 
This is one of the broods representing the extreme southern range of 
the Cicada, and was recorded by Doctor Smith in Florida as occurring 
in 1844 and 1857. Its existence was confirmed in 1870, when records 
were o])tained indicating its extension also into Alabama, Mississippi, 
and Tennessee. 
Tt is a brood which, according to re])ort, does not seem to occur in 
dense swarms, but scatteringly, at least in its more northern range. 
