ANOURA: HYLOIDJE. 311 



The Pickerel-frog, R. palustris, LeC., of the Northern 

 States and southward, is two and three quarters inches 

 long, slender, pale brown above, marked with dark brown 

 square spots ; under parts yellowish white ; posterior 

 half of the thighs bright yellow mottled with black. Its 

 flesh is delicate, and often used as pickerel bait. Its call 

 is a singular prolonged grating sound, which it utters 

 while floating on the surface of the water. 



The Wood-frog, R. sylvatica, LeC., of the Northern 

 States and southward, is about two inches long, pale red- 

 dish brown above, yellowish white beneath, head with a 

 dark brown stripe on the side. It is found in woods, and 

 frequents water only early in spring, when it lays its eggs. 



The Genus CystignatJms is represented by C. ornatus, 

 Holbr., of South Carolina, one and a quarter inches long ; 

 and C. nigritus, Holbr., of Georgia and Carolina, one and 

 a half inches long. 



HYLOID/E, OR TREE-TOAD FAMILY. This Family 

 comprises frogs which have the extremities of the toes 

 and fingers enlarged into a disk or viscous pellet, by 

 means of which they sustain themselves on the sides of 

 trees, branches, leaves, and all kinds of smooth surfaces. 

 They inhabit trees, shrubs, or plants, except in the breed- 

 ing season, when they resort to the water. 



The Genus Hyla comprises Tree-frogs or Tree-toads. 



The Tree-toad, H. versicolor, LeC., of the Northern and 

 Middle States, is two inches long, flattened, warty above, 

 color varying from palest ash to dark brown, with several 

 large irregular blotches of brown. The under surface is 

 mainly white, granulated. It is very noisy towards even- 

 ing and in cloudy weather, or before a rain. In the latter 

 part of spring or early summer it resorts to the pools to 

 lay its eggs. 



The Green Tree-frog, H. viridis, Laurenti, of the South- 

 ern States, is one and three quarters inches long. Sev- 



