486 



ZOOLOGICAL SOCIETY BULLETIN. 





FOUR STAGES OF DEVELOPMENT OF THE FROG. 



tics of the fisheries of the Mississippi River and 

 its tributaries, the single item of frogs for that 

 region was stated at 336,049 pounds, valued at 

 $24,783. The Fish Commissioner of Pennsyl- 

 vania has recently stated that the annual catch 

 of wild frogs in the United States is worth fully 

 $200,000 to the consumer. It is officially re- 

 ported that more frogs are taken in New York 

 than in any other State. 



The American bullfrog, {Rana catesbiana), is 

 not only larger than the edible frogs of Europe, 

 but the largest of all frogs. We have also a 

 few other species which grow large enough to 

 be important for food, such as the spring frog. 

 {Rana virescens), the green frog, {Rana cla- 

 mata), the leopard frog, {Rana pipiens), and 

 some western species; but the bullfrog and the 

 green frog are the largest and most promising. 

 The}' are also widely distributed, being found 

 throughout the entire Eastern and Middle 

 States. 



According to Government fishery statistics, 

 the first value of frogs sent to market averages 

 fourteen cents a pound, but in some sections the 

 prices received are much greater. They also 

 depend largely on the size of the frogs. 



The cultivation of frogs in paying quantities 

 is complicated by their peculiar habits, depend- 

 ence upon live food, cannibalistic tendencies and 

 numerous natural enemies. 



The procuring of eggs is not difficult, since 

 they may be found in all sorts of ponds and 

 stagnant waters early in the spring. The eggs 

 are deposited in jelly-like masses in shallow 

 water and are easily dipped up and transferred. 

 They can be hatched in wire-bottomed troughs 

 anchored in flowing water, and will of course 

 hatch in the ponds where they are found if the 

 egg masses are protected. The eggs hatch in a 

 Week or two, according to temperature. Toad 

 eggs need not be mistaken for frog eggs, since 

 the former are not laid in masses but in strings. 

 In the tadpole as well as the mature stage, frogs 

 have many natural enemies, both on land and 

 in the water. They are eaten by many kinds 

 of birds, snakes, fishes and small mammals. 

 The larvae of water beetles are especially de- 

 structive to the tadpoles, and if the beetles are 

 not constantly removed with a net, thousands 

 of tadpoles will be destroyed by the larvse in the 

 pond every day. The feeding of tadpoles is not 

 difficult. They devour dead animal matter of 

 all sorts and will swarm thickly around meat, 

 liver or fish, consuming it rapidly. 



After they develop into frogs live food is 

 necessary. They eat worms, beetles, spiders, 

 crickets, grasshoppers, caterpillars, crayfishes, 

 small frogs and fishes, in fact, any living thing 

 they are able to swallow. 



