l8o VERTEBRATE ANIMALS OF THE UNITED STATES 



Ci With conspicuous large, rounded, elongate or squarish 

 spots between the dorso-lateral ridges, 

 di Skin smooth, with usually 2 rows of spots between 

 the dorso-lateral folds, 

 ei Spots rounded or elongate; color tone of body 

 green, 

 f 1 Total length three and a half times the length 



of the head R. pipiens. 



U Total length two and a half times the length 



of the head; ear with a white center R. sphenocephala. 



e-i Spots squarish; color tone of body brown R. paliistris. 



d2 Skin warty; numerous spots on the back and sides. 



Ci Total length three times the length of head . . . R. areolata. 

 62 Total length two and a half times the length of 



head R. cesopus. 



C2 Without large spots on the back. 



di Large aquatic frogs; head green . . .R. clamitans. 



dj Small wood-frogs; head brown. 



Ci Length of leg to the heel exceeds total length of 



body R. sylvatica. 



62 Length of leg to the heel less than or equal to 



total length of body R. cantahrigensis. 



hi Dorso-lateral ridges absent. 



Ci Very large frogs, upwards of 200 mm. long R. catesbeiana. 



Co Smaller, medium sized frogs, under 100 mm. long, 

 di In the northern and central States. 



ei Back mottled R. septentrianalis . 



t'l Back plain, not mottled R. virgatipes. 



d2 In the Gulf States R. grylio. 



a2 On the Pacific slope and in the Rocky Mountain region ; dorso- 

 lateral ridges present, 

 bi Skin usually smooth. 



Ci A black cheek patch present R. aurora. 



C2 No black cheek patch present R. onca. 



b2 Skin tubercular. 



Ci Tympanum concealed; no red on belly R. boyli. 



C2 Tympanum exposed; belly and flanks with much red. 



di On the Pacific slope R. draytoni. 



do In the Great Basin R. pretiosa. 



R. pipiens Schreber. Leopard frog (Fig. 93). Body green, gray or 

 brown above with light-colored dorso-lateral ridges, between which are 

 I to 3 irregular rows of elongate or rounded dark spots, each edged with 

 yellow or white; similar spots on the flanks and legs; belly white; length 

 90 mm.; hind leg 150 mm.: North America, east of the Sierras; south- 

 ward into Mexico; the commonest frog; in ponds, marshes and meadows, 

 often at a considerable distance from water. 



