The Common Tree Frog 



ally watched him sing. At dusk or on rainy days a loud resonant 

 trill comes from the trees and vines. The sound has the charm of 

 contentment in it; in fact it is much like the purring of a cat, only 

 louder. At a distance it sounds something like the bleating of a 

 lamb. The pitch is uniform, but may vary with the individual, 

 from G above middle C to E above. It continues for two or three 

 seconds at a time, then ends abruptly. It may be given several 

 times in rather close succession. If we see the tree frog trilling, 

 we are surprised that the whole body is so greatly agitated and 

 that the throat extends into so large a sac. The size of the sac 

 decreases between each two trills and at the end collapses, leaving 

 a very wrinkled throat. 



The fact that the tree frog calls during damp weather, and 

 therefore often before storms, has made him accepted as a weather 

 prophet; however, he can scarcely be called a reliable one. 



The Common Tree Frog measures about two inches in length. 

 The head is broad and blunt, the body is fat and squat. The skin 

 is granular and has the appearance of being much too large for 

 the frog. The tree frog is like the frogs in having teeth on the 

 upper jaw. The eye is large; the ear is inconspicuous. The 

 fingers and toes have their ends extended into broad disks that 

 secrete a sticky substance on their lower surfaces. The toes are 

 webbed as far as the disks; the fingers are webbed nearly one- 

 third of their length. The male and female are more nearly alike 

 than is usual among tree frogs. They may not differ in size or 

 color, except that the throat of the male is dark. They can be 

 distinguished from one another by the ears, which are always 

 smaller in the female than in the male. 



The colour varies greatly at difi^erent times and in different con- 

 ditions. (See Colour Plate VI) In bright light and high temper- 

 ature it may be yellowish white with no markings. In a dark, 

 moist or cool place, it may be a deep stone-grey or brown. Most 

 often, perhaps, it is bright grey with dark markings. The most 

 conspicuous of the markings are the two bands on each leg and 

 each arm, and the irregular star on the upper part of the back. 

 There is usually a conspicuous lighter spot just below the 

 posterior half of the eye. This tree frog can always be distingu- 

 ished from tree frogs resembling it by the vermiculations of brown 

 and yellow on the concealed leg surfaces. (See Colour Plate VI.) 



However, we have not exhausted this tree frog's possible 



119 



