THE VERTEBRATE ANIMALS 



291 



toad that laid them. This apparent discrepancy is caused by the swelling 

 of the gelatinous substance around them. If possible, count the number 

 of eggs laid by one female.' 



Toad tadpoles may be distinguished from those of the frog, as 

 they are darker in color, and have a more slender tail and a rela- 

 tively larger body than those of the frog. The metamorphosis 

 occupies only about two months in the vicinity of New York, 

 but varies greatly with the temperature. During the warm 

 weather the tail is absorbed with wonderful rapidity, and the 

 change from a tadpole with no legs to that of the small toad 

 living on land is often accomplished in a few hours. This has 

 given rise to the story that it has rained toads, because during the 

 night thousands of young toads have changed their habitat from 

 the water to the land. 



The toad is of great economic importance to man because of its 

 diet. No less than eighty-three species of insects, mostly injurious, 

 have been proved to enter into the dietary.^ A toad has been ob- 

 served to snap up one hundred and twenty-eight flies in half an 

 hour. Thus at a low estimate it could easily destroy one hundred 

 insects during a day and do an immense service to the garden 

 during the summer. It has been estimated by Kirkland that a 

 single toad may, on account of the cutworms which it kills, be worth 

 $19.88 each season it 

 lives if the damage 

 done by each cut- 

 worm be estimated at 

 only one cent. Toads 

 also feed upon slugs 

 and other garden 

 pests. 



Other Amphibians. — 

 The tree frogs (called 

 tree toads) are familiar 

 to us in the early spring as thf " pocpor.s " of the swamjis. They are 

 among the earliest of the frogs to lay their eggs. During mlult life they 

 spend most of their time on the trunks of trees, where thciy receivo im- 



• See Hodge, Nature Study and Life. 



' See Kirkland, Habits, Foorl, and Economic Importance of the American Toad. 

 Bui. 46, Hatch Experiment Station, Amhorat, Mass. 



Spotted salamander. From photoEiaph loaned by 

 the American Museum of Natural History. 



