224 BULLETIN OF THE 



other allied species, the Chrysomitris pinus, and figures 13 and 13a 

 to 1j and 15a, inclusive (same plate) similar variations in another 

 species (Curviroslra americana), of the same sub-family. In the latter 

 case the specimens are also all males, and all from the vicinity of Cam- 

 bridge, they having been killed in fact from the same flock. In the 

 jEgiotkus group numerous so-called " species " have been described by 

 different writers, six or seven of which were recognized by Dr. 

 Coues a few years since in his monograph of that genus.* A consid- 

 erable number of these species have been generally looked upon as 

 equivocal, and the exact number in the group and their distinctive 

 characteristics have been a matter of much uncertainty. Recently the 

 writer above referred to has again revised the group,f and arrives at 

 the conclusion that if more than one species exists, all the forms pre- 

 viously recognized by him as species are valid species. I can readily 

 grant this alternative, being fully convinced that the genus consists of 

 but a single known species, which has a circumpolar distribution. The 

 alleged specific distinctions have consisted in differences in general 

 size, in the relative size of the bill, the length of the tarsus, wing, and 

 tail, and in color. Some of these differences are doubtless climatic and 

 local, while others may be due to age, but the greater part I believe to 

 be to a great degree purely individual, inasmuch as they are paralleled 

 in allied species, whose standing has not been and cannot reasonably be 

 questioned. But the special consideration of the variations presented 

 by the JEtjiotla and similar groups will be reserved till after the facts 

 relating to geographical variation have been presented, since they can 

 then be move appropriately discussed. 



Figures 1G and IGa to 18 and 18<7, inclusive (Flate V), represent 

 the bills of three male specimens of Pusserculus savanna, from different 

 localities on the Atlantic coast. The specimen represented in figures 

 18 and 18c?, has the bill of minimum size, being in bulk less than half 

 that of the one represented in figures 17 and 17a. \ Figure 17, it will 

 be observed, corresponds nearly with the so-called P. sandwichensis § of 



* A Monograph of the genus JEgiolhus, etc., Proc. Phil. Acad. Nat. Sci., Vol. XII, p. 



1. Vol. XV, p. 4", 1SG3. 

 j On variations in the plumage of the jEgiotki, Ibid., Vol. XXI, p. — , 1869. 

 J Other specimens received from Grinnell, Iowa, from Professor II. \V. Parker, since 

 the above was written, have lulls still smaller than any of those here figured. 

 § ISaird's Birds of N. Amer., p. 444, 1858. 



