686 BULLETIN 50, UNITED STATES NATIONAL MUSEUM. 



Adult M«Z6.— Length (skins), 128-129 (128.5); wing, 56-57 (56.5); 

 tail, 59-61 (60); exposed culmen, 10; tarsus, 20.5; middle toe, 13.5.^ 

 State of Hidalgo (Real del Monte; Tulancingo), southeastern Mexico. 



Genus CHAM^^THLYPIS Ridgway. 



Chamidhlypis Ridgway, Man. N. Am. Birds, Sept., 1887, 525. (Type, Geothlypis 

 poliocephala Baird. ) 



Similar in general appearance to Geothlypis^ but tail longer than 

 wing, graduated;'' bill ver}^ stout, with culmen strongly curved (nuich 

 as in Icteria)\ tarsus nearly half as long as wing, or at least much 

 nearer one-half than one-third as long; no black on forehead nor auricu- 

 lars in adult males; sexes alike, or at least not very different, in color. 



Bill much shorter than head, stout (depth at base equal to nearly 

 half the length of exposed culmen); culmen strongly curved; max- 

 illary tomium distinctl}^ concave or arched, with distinct subterminal 

 notch; mandibular tomium slightly but distinctl}'^ convex; gonys nearly 

 straight. Nostril longitudinally oval, in lower anterior portion of 

 nasal fossse, overhung by a broad membraneous operculum. Rictal 

 bristles obsolete. Wing short, much rounded (seventh, sixth, and 

 fifth primaries longest, ninth shorter than fourth or about equal to 

 third); wing-tip shorter than exposed culmen. Tail decidedly longer 

 than wing, graduated, the rectrices acuminate or subacuminate at tip. 

 Tarsus nearly half as long as wing, or at least very much more than 

 one-third as long, its scutella indistinct or obsolete on outer side; 

 middle toe, with claw, much shorter than tarsus; basal phalanx of middle 

 toe united for basal half (or slightly more) to outer toe, separated for 

 most of its length from inner toe. 



Coloration. — Olive-greenish above, yellow or yellowish beneath; 

 adults with pileum gra}' and lores black. Sexes alike, or nearly so. 



Nidlficat'wn . — Unknown. 



Jiange. — Northern Mexico (including southern Texas) to Chiriqui. 



This genus is very much like Geot/th/jjis as to general appearance, 

 but quite distinct structurally, in which respect it comes much nearer 

 to Icterla. From the latter it differs in its shorter and more rounded 

 wing, more graduated tail with pointed rectrices, longer tarsi, and 

 stouter feet. 



KEY TO THE SPECIES AND SUBSPECIES OF CHAM.ETHLYPIS. 



a. A white or pale yellow spot on each eyelid (largest on the lower). {Chamxthlypis 

 poliocephala. ) 

 6. Crown gray; lores black. (Adults.) 



^ Two specimens; a third, too much worn for measurement of wing and tail, agrees 

 with the other two in absence of any gray on the head; the exposed culmen measures 

 10, the tarsus 20. 



2 Only one species among the seventeen of Geothlypis has the tail longer than the 

 wing. 



