388 U. S P R. R. EXP. AND SURVEYS — ZOOLOGY — GENERAL REPORT. 



In the group, as defined above, are embraced several genera of modern systematists. Thus 

 the true black-capped American titmice are placed under Poecile of Kaup, where possibly they 

 belong. The species may be arranged as follows : 



A. Head and neck above and below entirely black ; their sides white. {Poecile.) 



Outer tail feathers and the tertiaries conspicuously edged with white. Outer edges of 

 greater wing coverts also nearly white. 



Largest. Wing, 2.70 inches; tail much rounded, or even graduated, exceeding 3.00, 



or longer than wings P. septentrionalis. 



Wing and tail about 2.50 inches, ani nearly equal. Tail nearly even. Body 



beneath white, tinged on the sides with brownish yellow P. atricapillus. 



Size and shape much like the last. Tail more rounded. Beneath pale yellowish 



rufous brown, lighter only along the median line P. occidentalis. 



Outer tail feathers and the tertiaries pale grayish, not white. Greater wing coverts 

 without paler edges. Tail nearly even, shorter than the wing. 



Wing, about 2.60 inches; tail, 2.45. Beneath plumbeous; similar to the back, 



only paler P. meridionalis. 



Smaller. Beneath white, faintly tinged with reddish brown, con8i)icuously 

 different from the back P. carolinensis. 



B. Crown and throat black, with white frontal and superciliary stripe. 



Above plumbeous; beneath white P. montanus. 



C. Throat sooty brownish ; sides of body bright reddish brown. 



Back and wing coverts chestnut brown ; crown not very different from the 



throat P. rufeacens. 



Back grayish olive brown. Crown similar.... P. hudsonius. 



Comparative measurements of species. 



* Veiy poor •peclmen. 



