160 TRANSACTIONS OF THE [1893 



TIBICEN, Lat. 



1. T. septendecim Linn. [Cicada), Syst. Nat. ed. XII., 



1767, Pars. 2, ^. 708, IS'o. 20. Cicada septemdecim 

 Oliv. Encyc. Method, v. 5, p. 749, No. 13. Tetti- 

 gofiia costalis Fabr. Ent. Syst. Supp. p. 516, No. 22. 

 Tettigonia costalis Coquebert Illust. 1, pi. 9, fig. 2. 

 Cicada septendecim Gfermar, Tlion. Ent. Arcliiv. 2, p. 

 4, No. 43. Cicada tredecim Hiley, First Report 

 Missouri, p. 19, is tlie race wliicli appears at inter- 

 vals of thirteen years, cliiefly in tlie region south of 

 the Ohio river. The dwarfed and modified form, 

 which appears late in the season, belongs to both 

 the 17 and 13 year races. It has been described by 

 Dr. Fisher as Cicada cassinii, Philad. Acad, Nat. Sci. 

 Proceed, v. 5, 1851, p. 272. 



Observations are needed to establish the length of 

 underground life required to develop some of the forms 

 of this species. That one of them which has the C. 

 cassinii as its last term, and which gives forth the more 

 prolonged and hissing note, seems to be in a state of 

 transition. It comes forth fully grown almost every year 

 in the region north and southeast of Baltimore, and that 

 too from the very spots whence the normal septendecim, 

 issued in 1868 and 1885. Specimens were collected by 

 myself at several marked points every year between 

 1880 and 1885, and I have received specimens of the 

 same, through the agency of friends, every year since 

 down to 1890. I am impelled to the belief that these 

 creatures undergo periods of rest in the young stages, 

 varying in length, and not yet defined by writers upon 

 this species. 



2. T. rimosa Say. Journ. Acad. Nat. Sci. Philada. vol. 



VI., p. 235, 2. Cicada noveboracefisis Fitch, Agricult. 

 of New York. Insects by E. Emmons, p. 152, pi. 9, 

 fig. 6. 



