202 BULLETIN OF THE 



Carolinas. Though no other difference was appreciable, he and his friend 

 Bachinan thought this was sufficient to warrant the description of the 

 southern form as specifically distinct from the northern. He accordingly 

 thus separated them in the second volume of his " Ornithological Biog- 

 raphy." But if the black-capped titmice of the Carolinas, the lower 

 parts of Virginia, Maryland, and Southern New Jersey are distinct from 

 those of Massachusetts, on precisely the same grounds are those of Mas- 

 sachusetts distinct from those of Northern Maine. Even the titmice 

 of Massachusetts are not just the same in winter that they are in 

 summer, those which breed here doubtless mainly going south in winter, 

 while their place is filled by others that spend the summer more to the 

 northward. This at least is what the slight average difference in size 

 between summer and winter specimens seems to indicate. But the Caro- 

 lina titmouse (P. carolinensis) has been recognized as valid by most 

 subsequent writers, and in accordance with the principle upon which this 

 supposed species was admitted, several others have been added by other 

 authors. 



The titmice from the middle, elevated regions of the continent, in 

 accordance with a general law of geographical variation among both birds 

 and mammals, are a little larger than those of either the Mississippi 

 valley or the Pacific coast, and have also, apparently, a relatively slightly 

 longer tail and paler colors, — variations which occur in a number of other 

 birds that have a similar distribution. The titmice of this region form 

 the Parus septentrionalis of authors. Specimens labelled " Parus septen- 

 trionalis," collected near Chicago, have been received at the Museum of 

 Comparative Zoology from the Chicago Academy. They do not differ, 

 however, from numerous others collected in Massachusetts, though the 

 true P. septentrionalis, or the black-capped titmice of the Rocky Moun- 

 tains, does have a slightly longer tail than those from the other parts of the 

 continent. 



Those which occur on the Pacific slope of the continent, though forming 

 the P. occidentulis of authors, are admittedly the same in size and general 

 appearance as the P. atricapillus of the Atlantic States, Ibis species having 

 been introduced to the world with the following suggestive remarks: 

 "It is rather a hazardous undertaking to add another to the list of North 

 American black-capped and throated titmice; but if we have three good 

 species now, instead of one, then the present is equally entitled to specific 

 distinction with carolinensis and septentrionalis." 



The P. meridionalis was first made known from a single specimen from 

 Mexico, and of which very tew specimens seem to have been recognized as 

 belonging to it. The original type certainly recalls only a worn summer 

 specimen of the common titmouse, though its darker color may be due to 



