BEHAVIOR AND COLOR CHANGES OF TREE FROGS 57 



friend, and about the same place found another specimen — 

 possibly one of the same. We paused and I took occasion 

 to point out some of the peculiarities already mentioned. 

 Reflecting on the matter it occurred to me that perhaps some 

 more painstaking observations, or possibly experiments might 

 prove worth while. Accordingly on my next trip that way 

 an observant eye was kept alert to note other specimens. Fortu- 

 nately four were found, all occupying the same relative positions 

 on different posts, but with the curious difference that no two 

 were of the same color. One was very light, a whitish grey, 

 one green, the other two very dark, one almost black. This 

 was about ten o'clock, on October 10, and the day was bright 

 and warm, all the specimens being in the sun. Following 

 critical study of the specimens in position, they were then taken 

 and carried back to the laboratory for further observations. 



On a subsequent trip a few days later, several others were 

 found in same location and always in the same positions and 

 attitude. Of these one specimen was in shade, the others in 

 open sunlight, and all were very light in color. On still later 

 trips others were found, invariably in same general positions. 

 It seemingly made no difference as to the hour of day, whether 

 in sun or shade, whether the day were warm or cool ; in almost 

 every instance there was the same diversity of color markings 

 and intensity. It was this seeming anomaly which first en- 

 listed my attention and interest, though the peculiarity of 

 habitat already alluded to was also involved in the interest. 



EXPERIMENTS 



As already mentioned, one of the first features of the subject 

 to engage my attention was the seemingly extraordinary aspects 

 of color difference characterizing the several specimens found 

 under exactly the same environment. It is now my purpose 

 to briefly describe the observations and experiments by which 

 it was hoped some adequate explanation of the matter might 

 be secured. Repeated field trips were made in order to find, 

 if possible, some clue to the subject by a study of specimens 

 under their natural surroundings. 



On a previous page mention has been made of the records 

 of two of these trips. A third trip secured three additional 

 specimens; one was a very light whitish grey with the pig- 



