BALAMANDEB, FBOO, AND OTSEB AMPHIBIANS. 177 



The toad is nocturnal, hopping about when the birds are 

 asleep, and is exceedingly useful in destroying noxious in- 

 sects. The salamanders, toads, and frogs hibernate buried 

 in the mud at the bottom of ponds. 



Male toads and frogs are musical, the females being com- 

 paratively silent ; the Tocal organs of the male are more de- 

 veloped than in the females, and in the European edible 

 frog large sacs for producing a greater volume of sound 

 swell out on each side of the head of the males. 



The toad (Bu/o lentiginosus) is exceedingly useful as a 

 destroyer of noxious insects. It is harmless. In the 

 Northern States toads begin to make their peculiar low 

 trilling notes from the middle to the 20th of April ; from 

 the latter date until the first of June they lay their eggs in 



C D 



Fig. 184.— Different stages in the Metamorphosis of the Toad. 



long double strings, and the tadpoles are usually hatched in 

 about ten days after the eggs are laid. 



The toads and frogs after hatching pass through a wonderful 

 series of changes before reaching maturity. Fig. 184 repre- 

 sents the external changes of the toad from the time it is 

 ~^ hatched until the form of the adult is attained. The tadpoles 

 of our American toad are smaller and blacker in all stages of 

 growth than those of the frog. The tadpole is at first with- 

 out any limbs (Fig. 184, A ), and with two pairs of gills ; 

 soon the hinder pair bud out. After this stage [B) is 

 reached the body begins to diminish in size. Then the 

 fore-legs grow out ( C) ; and finally, as at D, the tail is 

 mostly absorbed, and at .5'we see the little toad which hops 

 about on the bank. 



