320 



CIVIC BIOLOGY 



iiiacliinery ? Could this be prevented? If so, how? Might it be worth 

 while, as a measure for insect control, to try the experiment of stocking 

 a farm with them, and comparing the damage done by insects on such 

 a farm with that on a similar farm where there are no toads ? 



Elementary classification and distribution. The names at the head of 

 this chapter present the main groups of amphibia in ascending order. 



They are placed there to serve 

 as handles bv which any form 

 that is of local interest or im- 

 portance may be looked uji 

 in the dictionaries, natural 

 liistories, or zoologies. 



Jordan's " ^Manual of Ver- 

 tebrates " describes eighty-one 

 species of salamanders for the 

 United States. So little is 

 known about their habits, 

 foods, s])awning seasons, and 

 general natural history, that 

 they offer an almost virgin 

 field for young American nat- 

 uralists — a field that needs 

 w^orking the more on account 

 of senseless prejudices con- 

 cerning the venomous char- 

 acter of these harmless and valuable aninuils. The mud puppy 

 (Necturus jnaculosiis) of the upper Mississippi and (xreat Lakes basins 

 destroys the spawn and young of fishes, but this is the only one of the 

 tailed amphibia that is considered harmful. 



Recent books describe fifty-three species of the tailless amphil)ia as 

 native to the United States — the frogs, tree frogs, and toads. Of the 

 fourteen species of toads the greater number occur in Texas and south- 

 western United States, indicating this region as the i)robable center 

 from which the group has spread over the continent. 



Fig. 153. Coast newt depositing eggs in 

 an aquarium 



Photograph by Loye Hohues INIiller 



