BAELY VOICES OF SPRING. 13 



I can imitate Hyla pickeringii by shrilly whistling 

 E slurred to F in the highest octave on the piano ; 

 I need a bass viol to imitate the bullfrog {Rana 

 caUsbiana) ; I am sure I do not know how to copy 

 the tree toad's note, unless by making a bleating 

 sound with the lips ; I must have a rattle whistle to 

 imitate the Aoris ; and I must hum one note and 

 whistle another to approximate the droning note of 

 the toad. A big chorus of the Hyla and Acris 

 sounds like jingling sleighbells; a medley of the 

 larger batrachians' voices is like the " tuning up " of 

 a string orchestra. 



Quite nearly related to the genus Chorophilus is 

 the genus Hyla,* one species of which {Hyla picksr- 

 ingii) I have already noticed. There are but two 

 other HyloB whose range extends north of North 

 Carolina : one is Hyla versicolor {ai the same range 

 as Hyla picJceringii), and the other is Hyla am.der- 



* The genus Hyla includes fully one half of the large Hylidm 

 family, which seems to have been created to inhabit the leafy part 

 of the world — especially the tropical part — for the special purpose 

 of holding in check the prolific insect life which might otherwise 

 do an inestimable amount of injury to vegetation. It is the case, 

 therefore, that in those regions where vegetable life abounds there 

 is a proportional increase in the number of species. I question 

 very much whether one could conscientiously kill a toad or a frog 

 who had a full knowledge of the immense number of insects it 

 devoured within a year's time, and the extent of harm that these 

 might have worked on vegetation. 



