liej)files and Amphihians of Illinois. 319 



SYNOPSIS OF THE ILLINOIS SPECIES. 



1(2). With distinct dark spots above, arranged in more 

 or less perfect longitudinal rows 3. 



2(1). Spots, when present, obscure and not arranged in 

 longitudinal rows 9. 



3 ( 4). With more than two complete rows of spots be- 

 tween the glandular folds of the back. 



R. AREOLATA. 



4(3). With but two complete rows of spots between the 

 glandular folds 5. 



5 ( 8). Spots oval or nearly round; glandular folds narrow 



and elevated 6. 



6 ( 7). Spots isolated, anterior of the three on the head 



small or wanting; males with saccular dilations 

 behind the angles of the mouth. 



R, UTRICULARIA. 



7(6). Spots not isolated, anterior of the three on the 

 head about equal to the others ; males without 

 saccular dilations R. pipiens. 



8 ( 5). Spots squarish ; glandular folds wide and depressed. 



R. PALUSTRIS. 



9 (11). With distinct glandular folds on the sides of the 



back; size small or medium 10. 



10 (12). Tympanum large. No distinct dark spot extending 



from the nostril through the eye and including 

 the tympanum R. clamitans. 



11 ( 9). No, or very indistinct, glandular folds. Size very 



large R. catesbiana. 



12 (10). Tympanum very small; a distinct dark spot extend- 



ing from the nostril through the eye and includ- 

 ing the tympanum R. silvatica. 



Rana areolata, Bd. and Gir. 



Rana areolata, Bd. and Gir., Proc. Acad. Nat. Sci. Phila., 1852, 



VI., p. 173. 

 Rana capita, LeC. Proc, Acad. Nat. Sci. Phila., 1855, VIII., p. 425. 



