PROTECTIVE RESEMBLANCE, WITH EXAMPLES 75 



this larva would be quite interesting to determine. The bold- 

 ness and heroic courage of this httle tree-toad in attempting 

 to swallow so large a larva was admirable. But what must be 

 said of the courage of this same little batrachian which was 

 displayed a few minutes later! I happened to have at hand 

 a plump, half-grown larva of a large moth, Telea polyphemus. 

 This green larva had been feeding on the leaves of hazel and 

 was much larger than that of the saw-fly species. On seeing 

 this larva the toad at once seized it and in a few moments had 

 it half-way down, but after struggling some time with it 

 the toad again disgorged its bulky prey. I later supplied 

 the toad with its regular diet of beetles and small moths. 

 Occasionally it ate cabbage butterflies and small dragon-flies 

 which I caught in a net during the da^' and reserved for its 

 supper. 



The tree-toad varies much in color, depending on the back- 

 ground environment, humidity, and degree of light. On certain 

 occasions it changes from yellowish white to a deep gray or 

 brown, after moving to a new position in a darker place. 

 Similarly, sometimes it may change from white to a beautiful 

 green, or green and gray, if moved to a background of green 

 leaves. This color transformation requires about an hour's 

 time. The male and female are very similar in size and color, 

 the former being distinguished principally by his darker throat 

 and larger tympanum, or ear. This species can be distinguished 

 from other tree-toads by the orange-yellow or brownish con- 

 cealed coloring of the leg surfaces where they fold in contact. 

 The eggs are laid in the spring of the year in small clusters in 

 the water of ponds and marshes, and are attached to the stems 

 of plants. They hatch into tadpoles within two or three days 

 after they are laid. Dickerson states in her interesting "Frog- 

 Book" that about seven weeks are required for the tadpoles 

 to complete their metamorphosis. The little green frogs then 

 leave the water for their land excursions. 



I believe from observation that the tree-toads, when common 

 in a locality, exercise an important influence or control over 

 insect life, especially in beech forests and swamps, and act as 

 a selective factor. 



