22 



Zoologia: N. Y. Zoological Society. 



[Vol. 1 



From careful study of the general coloration of over fifty 

 specimens it appears that there is no radical variation in the 

 plumage as a whole in these doves from Arizona to Nicaragua. 

 From this region southward there is a hiatus, if not in actual 

 distribution, at least in the record of any individual of this genus. 

 In Colombia, on the South American mainland, we find Scarda- 

 fella ridgwayi, in which the white of the greater wing coverts is 

 very strongly marked and the dark, scale-like tips of the contour 

 feathers are nearlv twice as wide as in the northern birds. 



DIAGRAM OF FEATHER SHOWING MEASUREMENTS ON WHICH TABLES ARE BASED. 



Disregarding the boundary line of species and subspecies 

 for a reason which will appear later, and carefully tabulating the 

 variations in specimens from different localities, a very apparent, 

 grading of certain characters is found from the Arizona to the 

 Venezuelan birds. In Tables I, II, III and IV, which are self- 

 explanatory, I have given the averages for the size of the black- 

 ish tips of the outer pair of primaries, and the white tips of the 

 outer (or sixth) , fourth and third pairs of rectrices. The figures 

 are all in millimetres and the key to the method of measurement 

 is given in the above figure. 



TABLE I. 

 Geographical variation in the Blackish Tip of Outer Primary of Scardafella. 



It is to be regretted that so few specimens were available 

 for examination, fifty-seven all told, about ten from each group 



