THE PERIODICAL CICADA. 173 



THE PERIODICAL CICADA, alias, "SEVENTEEN-YEAR LOCUST." 



PROF. C. V. RILEY. 



The present year will be marked by a quite extended appearance of this in- 

 teresting insect, both a seventeen and a thirteen year brood simultaneously ap- 

 pearing. The readers of the Naturalist are doubtless familiar with the habits and 

 natural history of Cicada septemdecim Linn., and those of the thirteen-year race 

 {C. tredecim Riley) which agree with it in every respect except in the time re- 

 quired for full development. We will, therefore, simply quote here, with brief 

 comments, what was said in 1868, in the writer's First Report on the Insects of 

 Missouri, regarding the two broods that are to appear the present summer, and 

 that will be rendering the woods vocal with their rattling song, in the more south- 

 ern parts of the country, by the time the present number is out. 



BROOD XVII — SEPTEMDECIM — 1 864, 1 88 I. 



In 1 88 1, and at intervals of seventeen years thereafter, they will, in all prob- 

 ability, appear in Marquette and Green Lake counties, in Wisconsin, and may 

 also appear in the western part of North Carolina, and about Wheeling, Virginia; 

 in Northeast Ohio, and a few in Lancaster county, Pa., and Westchester Coun- 

 ty, New York. 



There is abundant evidence that they appeared in the counties named in 

 Wisconsin in 1864, and fair evidence that they appeared that year in Summit 

 county,. Northeast Ohio, while straggling specimens were found in the same year 

 by Mr. S. S. Rathvon, in Lancaster county, Pa., and by Mr. James Angus, in 



Westchester county. New York. Dr. Fitch also records their appearance in 

 1847, or seventeen years previously, in the western part of North Carolina, and 

 Dr. Smith, in Wheeling, Virginia, in 1830, '47, and '64. The distance between 

 the localities given is very great, and it is doubtful whether all these records be- 

 long to one and the same brood. 



BROOD XVIII — TREDECIM 1868, 1881. 



In the year 1881, and at intervals of thirteen years thereafter, they will, in 

 all probability, appear in Southern Illinois, throughout Missouri, with the excep- 

 tion of the northwestern corner, in Louisiana, Arkansas, Indian Territory, Ken- 

 tucky, Tennessee, Mississippi, Alabama, Georgia, and North and South Carolinas. 



Though, as already stated, I published the first account ever given of the ex- 

 istence of a thirteen-year brood, yet, besides the others mentioned in this 

 chronology, this particular brood has been traced since, as having occurred in 

 the years 1816, '29, '42, '55, and 68; and Mr. L. W. Lyon, at the July (1868) 

 meeting of the Alton (Ills.) Horticultural Society, even mentioned its appearance 

 in 1803. 



In Missouri it occurs more or less throughout the whole state, with the ex 

 ception of the northwest corner that is bounded on the east by Grand river, and 



