A CONTRIBUTION TO THE KNOWLEDGE OF THE VARIA- 

 TIONS OF THE TREE FROG HYLA REGILLA. 



By Frederick Cleveland Test, A. M., M. D., 



Sometime Aid, Department of Iteptiles. 



It would be difficult to cite a department of natural history, animal 

 or vegetable, that has not suflered more or less confusion from the 

 extensive synonomy possessed by some of its west American represen- 

 tatives. This has come about by the too ready and free description as 

 new of specimens brouj^ht in by the various Government exploring 

 expeditions, and also by private individuals, often meager material 

 collected at points whose ])recise location and geographical relation to 

 each other were many times but vaguely understood. With, then, no 

 intermediate forms at hand, and frequently with incomplete or no com- 

 parison with types already described from the same region, it is easy 

 to see how the multitude of names has sprung up. In the case of 

 alcoholic specimens, especially with batrachians, there was an addi- 

 tional source of danger froto imperfect preservation, for if the alcohol 

 were too strong the specimens would be hardened and contracted out 

 of their normal proportions, while if it were too weak they would be 

 macerated and relaxed, in either case rendering hable misidentification 

 and consetiuent duplication of species. 



The Pacific tree frog has not been neglected in the race for this sort 

 of distinction, and indeed is well-nigh a leader, no fewer than seven 

 names having been a[)plied by diflferent persons at various times to 

 hylas from beyond the Rockies. It is with the idea of making an 

 effort to clear up this ambiguity, which even the latest writers on the 

 subject have left almost as cloudy as before, that this paper has been 

 I)re])ared, and it is puri)osed to show that all the tree frogs of the 

 Pacific region, variant as they may seem at first glance, are really 

 referable to but a single species. The collection at hand in the U. 

 S. National Museum is the most extensive in existence, not only in 

 the number of specimens, but also in the number and distribution of 

 localities represented, comprising 512 specimens from 75 loc^alities, and 

 so a reasomilih^ amount of confidence is placed in the conclusions 

 reached from examining this mass of material. 



PROCEEOrNGS U. S. National Museum, Vol. XXI-No, 1156. 



477 



