THE SEVENTEEN-YEAR CICADA. 



97 



spiae shorter than ia that species, while the snag or supplementary tooth is larger and 

 nearer the end; the next spine, the basal one of the series of five, is three times as 

 large as the next one, while in C. pruinosa it is of the same size, or, if anything, 

 smaller. The toe joint (tarsus) projects over two thirds of the length beyond the end 

 of the shank (tibia), while in the other species it only projects half its length. The 

 terminal segment of the body is rather larger than in C. pruinosa. The body is shin- 

 ing gum-color or honey-yellow, with the hinder edge of the abdominal segments 

 thickened, but no darker than the rest of the body. Length, one inch (.90 to 1.00) ; 

 width, about a third of an inch (.35), being rather smaller than that of C. prninosa 

 and much larger than that of C. rimosa. 



Fig. 36.— The seventeen-year Cicada (c) and pupa (a, h): d, position of eggs (e) ; /, larva. (After Riley.) 



For a farther account of this Cicada the reader is referred to Prof. 

 Kiley'.s report of the U. S. Eutomologist for 1885, and to Bulletiu No. 8, 

 of the Division of Bntomoloffy, which contain full information regard- 

 ing the different broods which appear in different years. From his 

 observations it appears that the development of the larva is extremely 

 slow, and when six years old it hardly attains one-fourth its full size. 

 Moulting also takes place more than once a year, so that there are prob- 

 ably twenty-five or thirty changes of skin in all. Riley, also, has rarely 

 found it more than two feet below the surface during the first six or 

 seven years of its life, and almost invariably in an oval cell, and more 

 often away from roots than near them. Yet it can descend to great 

 depths, one writer stating that he had found it 20 feet below the sur- 

 face. ''A.S the time approaches for the issuing of the pupa it gradually 

 rises nearer and nearer to the surface, and, for a year or two before the 

 appearance of any given brood, this pupa may be dug up within one or 

 two feet of the surface." 

 5 ENT 7 



