from dangers from fish and some other enemies, but has its disadvantages in 

 times of drought. Upland or pickerel frogs and meadow or leopard frogs lay 

 a little later and in more permanent ponds. The former deposit eggs brown 

 above and yellowish below, the latter black and white eggs, which also transform 

 the same season. The American toad lays a bit later and prefers small ponds, 

 often adopting garden lily ponds. Fowler's toad lays about three weeks later, 

 and prefers more water, often utilizing quiet shallows of large lakes or streams. 

 The males of both species may be heard trilling at intervals during the summer. 

 The sluggards of the frog world are the green frog and the bullfrog, which do 

 not reproduce until early summer. Both produce large floating sheets of eggs. 

 Those of the green frog are usually among growing vegetation near shore, those 

 of the bullfrog among brush or twigs near the center of the pond. In both 

 cases the tadpoles pay the penalty for their parents' late appearance, the green 

 frog spending one winter and the bullfrog two or even three winters in the 

 tadpole stage. Eleutherodactylus ricordu, the robber frog of southern Florida, 

 and probably some of the frogs of the southwest, like a number of more south- 

 ern and tropical ones, lay their eggs on land, the tadpole stage being passed 

 within the egg. These frogs lay fewer and larger eggs than the water-laying 

 ones. 



Variations and sexual diiferences are marked among frogs. Coloration is 

 an unsatisfactory guide for identification. Many frogs become almost black 

 in dull weather or in dark surroundings and light or brightly colored in sun- 

 shine. The tree frogs are extreme in this regard, rivaling the chameleon. Im- 

 mature frogs are frequently spotted or marked differently from adults. The 

 green frog has an especially bewildering range of markings in its youth. Bufo 

 amencaniis and Bufo foiulen intergrade as far as markings and colors are con- 

 cerned, their voices being the best distinguishing characters. Several of the 

 other species of Bufo merge so that it is frequently very difficult or often im- 

 possible to tell certain specimens of one species from those of another. Many 

 colors, especially the reds and yellows, fade or disappear entirely in preserved 

 specimens. Sexual differences also exist. In most of the anurans the female 

 becomes larger than the male. In some of the Ranas the tympanum or outer 

 ear drum of the male is much larger than that of the female. In some frogs 

 and toads the male has a colored or dark throat, while the throat of the female 

 is usually white. The males of the true toads and of the spadcfoot toads have 

 a dark or black callus on each of the first two fingers. During the breeding 

 season the males of the Ranidae have the thumbs greatly enlarged. 



From time to time the American public is offered a "gold brick" in the 

 form of an opportunity to invest in frog farms. Frogs' legs arc an important 

 item of diet, but so far the market has been dependent upon the natural v.'ild 

 supply. Unfortunately the bullfrog, the only species that attains sufficient 

 size to be really desirable for food, takes from one to three years in the tadpole 



333 



