MUSEUM OF COMPARATIVE ZOOLOGY. 263 



its southern habitat. Towards the end of the breeding season specimens 

 of P. atricapillus, more especially females, have the plumage, particularly 

 that of the lower surface of the body, much darker than in fall and winter, 

 simply from the wearing off of the rufous and ashy extremities of the 

 leathers, July specimens generally differing much in color from winter ones. 



In respect to P. carolinensis, as already observed, the only difference 

 urged as distinguishing it from P. atricapillus is that of its smaller size. 

 Yet this difference is so slight that it is admitted that if P. carolinensis and 

 P. atricapillus were " separated by a wide interval of locality, it might be a 

 question whether it [P. carolinensis'] might not be a variety. As, how- 

 ever," it is urged, " both are found together in the Middle States, and pre- 

 serving together their characteristics, there will be little risk in considering 

 them distinct." Since the larger birds are, in the main, either northern 

 or occupy the elevated regions of the Alleghanies, the two forms must 

 necessarily be found associated together, especially in winter, through their 

 migrations. Unfortunately, in the work where this group has been most 

 elaborately considered,* but two examples of each are cited, with a state- 

 ment of their measurements ; the two of P. atricapillus being from Carlisle, 

 Pennsylvania, and the two of P. carolinensis from Washington, D. C. 

 From the annexed table of measurements of P. atricapillus from Massachu- 

 setts and Maine, it will be seen that a few are small enough to be regarded 

 as belonging to the P. carolinensis. There is, also, a larger amount 

 of seasonal difference in the color and general character of the plumage 

 than has been either admitted or suspected, as well as in size. No one 

 who has previously written on this group appears yet to have compared 

 many specimens of these supposed two species, or to have examined a 

 sufficiently large number of either to become aware of the wide differences 

 that exist between specimens from the same locality. 



Variations similar to those assumed to specifically distinguish P. caro- 

 linensis from P. atricapillus occur in P. hudsonicus between sj:>eeimens from 

 localities quite distant in latitude. Dr. Bryant has already called attention 

 to such differences in the P. hudsonicus, and at the same time proposed 

 for the southern "variety" the name of "P. hudsonicus var. littoralis." 

 Concerning this variety and the general subject in question, he remarks 

 as follows : " The specimens of Paras hudsonicus from Yarmouth [Nova 

 Scotia] and those from the Hudson Bay territory present as great, if not 

 greater, differences in size than exist between P. carolinensis and P. atri- 

 capillus, and in color, between P. septentrionalis and P. atricapillus. I am 

 inclined myself to consider P. atricapillus, septentrionalis, meridionalis, and 

 occidentalis as varieties of on" species; but, if they are considered as 

 specifically distinct, there can be little question of the propriety of 



* Baird's Birds of North America. 



