NO. 1156. 



VARIATIONS OF HYLA REGILLA—TEST. 



485 



lu the case of 31 specimens from Lower California, they are all of 

 so nearly the same size as to show no decided tendency, one way or 

 another,' as follows: 



Characters of Hyla regillafrom Lower California. 



In regard to whether there is a difference in color between the sexes, 

 the males appear to average a littleheavier marking than do the females, 

 as indicated by the following data: 



Characters ofvialea and females of Hyla regilla. 



Of the 108 males examined, 50 belong to the first three styles, and 

 58 to the latter two, thus throwing the average between styles III 

 and IV, and nearer to IV. Forty-one of the 85 females come under the 

 first two styles, so that they average between styles II and III, witli a 

 slight margin in favor of style III. These results are influenced, how- 

 ever, by the fact that the majority of the specimens from the south, 

 which are darker, are also males, while of the lighter specimens of the 

 north more females seem to have been collected. It is possible that 

 if the sexes were equally represented from each locality the average 

 coloration would be practically the same. 



In this connection comes up the point of distribution of color north 

 and south, hinted at above. The figures already given in showing the 

 relation between size and color indicate that northerly the first styles 

 of color are more numerously represented than in the south, and vice 

 versa. A color observation of 323 individuals bears out this indica- 

 tion and proves it to be a law. The following tables show the distri- 

 bution of color if the range of the species be divided into three sections — 

 north, middle, and south. 



'The fact, which then seems to be firmly established, that the younger Individuals 

 arc the lighter, and that they become gradually darker as they increase in size, 

 really would seem to indicate that the ancestral color was light and with few mark- 

 ings, were it not for the overwhelming testimony offered by allied forms that the 

 primitive appearance was darker, for it is hardly likely that they have all evolved 

 in the same color direction. At present the solution of the seeming contradiction 

 does not present itself. 



