42 FROGS. 



together with flies, replace the beetles of the adults. In the food of 

 the wood frog and of the pickerel frog this order of insects consti- 

 tutes 4 per cent, or less, and is a negligible factor in the green frog's 

 and bullfrog's diet. 



Orthoptera: Roaches, crickets, and grasshoppers make up a promi- 

 nent part of the food of the adult leopard, wood, and green frogs, 

 while mole crickets not infrequently enter into the diet of the bullfrog. 

 Orthoptera fm-nish 3 per cent of the animal food of the toad. 



Hemiptera: Bugs enter but slightly into the food of the wood frog 

 and bullfrog, form less than one-half per cent of the food of the toad, 4 

 per cent or less of the leopard frog's diet, 8 per cent of that of the 

 green frog, and 12 per cent or more of that of the pickerel frog. 



Diptera: Flies and their relatives form 1^ per cent of the food of 

 the leopard frog and one-half per cent of that of the toad. They are 

 rather a negligible factor in the food of the large forms, while in such 

 creatures as the cricket frog they may play a prominent r61e. 



Vertebrates. — Vertebrates enter but seldom into the diet of any 

 but the largest forms, such as the bullfrog. Dyche'* records the finding 

 of bullheads, crappies, sunfish, goldfish, bullfrog, and other frog tad- 

 poles in the stomachs of bullfrogs. There are extant records of 

 unusual food, like young ducklings, sparrows, mice, snakes, and young 

 newly hatched alligators, in the food of this same species. The other 

 frogs are too small of maw to essay the devouring of any vertebrates. 



ENEMIES. 



No article is more sought for or more relished as a food by a diver- 

 sity of animals from fish to man than frogs. The latter's deiense con- 

 sists in concealment and in the possession of poison glands in the skin, 

 neither of which means is aggressive in its nature, insects and plants 

 may prove a more constant fare, but to any fair-sized animal a frog 

 diet is one of the preferable menus, if obtamable. 



Invertebrates: One would naturally thmk the insect and small 

 animal life of the inland waters was a negligible factor in the reduction 

 of the number of frogs, tree toads, and toads. But for the tender 

 early larval stages and even for the more mature tadpoles these are 

 very serious foes. Anyone who has collected a miscellaneous mass 

 of aquatic life and put it all m one jar knows from dear and sad 

 experience that these small creatures of the water often prey upon 

 and kill the confined tadpoles and small frogs. In the open, es- 

 pecially at night, has the writer seen adult peepers and swamp 

 cricket frogs or their tadpoles in the fatal grip of giant water bugs. 

 Other aquatic bugs, like the well-known Zaitha, walking sticks, and, 

 not least, the back swimmers, make life precarious for tadpoles or 

 miserable for adult frogs in the water. '^The water beetles, especially 

 their larvae (water tigers) and dragonfly nymphs also take their 

 heavy toll of tadpole lives. Many of the smaller, almost microscopic, 

 crustaceans, like daphnia and others, are reputed to be incessant 

 enemies covering the whole bodies of the tadpoles. Some of the 

 larger Crustacea, like the crayfish, may possibly take the live tadpoles, 

 but it can not be definitely stated that they do. . Mosquitoes, gnats, 

 etc., pester frogs and tree frogs when out of the water, but in general 

 little is known of this matter, because it usually happens at night 

 when man is seldom observant. 



aDyche, L, L.: Loc. cit., pp. 150-153. 



