CHRONOLOGICAL ACCOUNT OF DIFFERENT BROODS. 21 
the Wisconsin River to its mouth. There seems also to be a detached 
branch commencing about the middle of the northern part of Low: 
County and running across the Wisconsin River into Sauk County. In- 
cidentally with his studies on Brood XIII, Prof. C. E. Bessey, of Ames, 
Iowa, was able in 18:8 to define the boundary of this Brood V_ of 
1871, and to illustrate its extent in his State by a map published in the 
Towa Weather Bulletin for November, 1878. The brood occupies nearly 
the whole eastern third of the State, not reaching, however, the south- 
eastern corner and being limited toward the west by a line drawn from 
Mitchell County to a point on the Mississippi River somewhat south of 
the mouth of the Iowa River. In its southeastern portion this brood 
overlaps, therefore, Brood XIII. In Illinois the boundary line, in a gen- 
eral way, may be drawn from the northwest portion of Mercer County, 
southeast to the Illinois River at Peoria, west along the Toledo, Wabash 
and Western Railroad. There seem to be detachmeuts extending far- 
ther south, especially in the eastern portion of the State, and they oe- 
curred as far south as Shelby County. In Indiana the line is not well 
defined, but includes the extreme northwest counties, extending as far 
south as the Kankakee River. In Michigan it does not extend north as 
far as Saint Joseph on Lake Michigan. 
As this insect can only appear in districts which were timbered or 
planted to orchard seventeen years ago, it follows that in such an ex- 
tensive prairie country as that within the limits indicated, the brood 
must be very much detached and scattered. 
The insects did not appear in the Pequea Valley, in Lancaster County, 
Pennsylvania; at least I have been unable to get any authentic record 
of the fact. 
From all I can learn, no Cicadas appeared at Plymouth, Mass., a fact 
which corroborates the view expressed in 1868, that the visit recorded 
by Morton in 1633 was a premature one, and that it was due in 1654. 
The southern boundary of this brood in Illinois needs further defi- 
nition. Mr. A. C. Hammond, of Warsaw, Hancock County, wrote me 
that in 1871 it did not occur at Warsaw, and the same statement was 
made to me by Mr. M. L. Dunlap in regard to the vicinity of Cham- 
paign. 
Mr. S. S. Rathvon, of Lancaster, Pa., subsequenily (May 17, 1572) 
informed me by letter that he had also failed in 1871 to hear anything 
of this brood in Pennsylvania. 
Belated individuals of this brood were reported to me by Mr. E. 8. L. 
Richardson, from Oswego, Kendall County, Hlinois, on June 20, 1872, 
who also states at the same time that the Cicadas were there in 1837, 
1854, and 1871. 
Broop VI.—Tredecim—1884, 1297. 
In the year 1871, being the same year as the preceding, and at intervals ot thirteen 
years thereafter, they will, in all probability, appear in the extreme southwestern 
