TREE-TOADS. 185 



spawn at two seasons instead of ono, and that their larvse 

 attain a greater size tlian those of other frogs before com- 

 pleting tlieir metamorphosis. 



Among the tree- toads, Polypedates of tropical Western 

 Africa, contrary to the usual habits of frogs, deposits its 

 eggs in a mass of jelly attached to the leaves of trees which 

 border the shore overhanging a pond. On the arrival of 

 the rainy season, the eggs become washed into the pond 

 below, where they develop. Onr common piping tree-toad 

 {Hyla Pickcringii), abont the middle of Api-il, in the 

 Northern States, attaches her eggs singly to aquatic plants. 

 The young are hatched in about twelve days. 



Miss Hinckley has described the habits of the larger tree- 

 toad {Hyla versicolor, Fig. 231). The eggs are attached 

 from early May till July, singly and in small groups in 

 grass which grows np and rests on the water. The tadpoles 

 hatch in two days. In a week after the tadpoles appear 

 the gills are alisorbed. Meanwhile the tadpoles hang by 

 their "holders," or suckers on the lips, to the leaves, as 

 seen in the engraving. When about three weeks old the 

 hind legs begin to bud out in front of the base of the tail. 

 During the eighth week they take little food; the four legs 

 grow out, the tail disapjiears, the mouth becomes adapted 

 for seizing and eating insects, and they leave the water. 

 This tree-toad depends for safety on its power of changing 

 its color from green to gray; it hides among leaves, or in 

 crevices in the bnrk of ti-ees, when it becomes "like a 

 part of the bark of the tree." 



As an example of what is called a suppressed metamor- 

 phosis may be cited the case of a tree-toad in the island of 

 Guadaloupe. There are no marshes on this island, conse- 

 quently in a species of Hylocles the development of the 

 young is direct; they hatch from the eggs which are laid 

 under moist leaves, without tails, and are otherwise, ex- 

 cept in size, like the adults. On the other hand, a tree- 

 toad of tlie island of Martinique {Hylodes 3Iarfinicensis, 

 Fig. 233) has tadpoles, which it carries on its back. The 



