586 BULLETIN 203, UNITED STATES NATIONAL MUSEUM 



describes the immature plumage as "similar in general to the adult 

 plumage, but duller, the pileum concolor with back, or nearly so, 

 and lores dull brownish gray or dusky, not distinctly different from 

 color of pileum." The adults in fall and winter are "similar to the 

 spring and summer plumage, but plumage softer, more blended ; back, 

 etc., more buffy olive or light olive-brown; feathers of pileum (at 

 least the occiput) tipped with brown, and flanks more decidedly 

 buffy." 



Chapman (1907) says of the adult spring plumage: "Crown slaty 

 with a slight olive wash, lores black, this color extending below the 

 eye ; a white mark on eye-ring above and below the eye ; back, wings 

 and tail olive-green without white markings, bend of wing yellow; 

 throat and breast bright yellow becoming paler on the belly and 

 brownish on the flanks." 



In the adult female the black on the lores, so prominent in the male, 

 is much restricted or nearly or quite lacking. 



Dr. Wetmore (1943) writes of this species in southern Veracruz : 



This is a resident species, common in the Tres Zapotes region wherever bushes 

 are scattered through the grasslands. They kept under cover ordinarily, flying 

 out occasionally as I passed, or were seen as they sang from the tops of bushes 

 or tall grass stems. The song is a low, rather inconsequential warble of several 

 notes. I had a better view of them at times in crossing these savannas on mule 

 back, as then from the elevation of the saddle I could see about more, and the 

 birds were less wary. They tend always to be inconspicuous and to slip aside. 

 They suggested the yellowthroats of the north in most of their habits. • • * 



On comparison of material in the U. S. National Museum it is evident that 

 specimens from near Brownsville, Tex., in the lower Rio Grande "Valley, differ 

 from typical poliocephala in significantly paler color, with less yellow on the 

 lower surface. They are to be separated therefore as Chamaethlypis poliocephala 

 ralphi (Ridgway) in spite of the fact that Ridgway in his last account of the 

 species placed the Texas birds under tjT)ical poUocepTiala. With a good series 

 of skins the differences are clearly evident. 



In his earlier description of ralphi, Ridgway (1894) calls it similar to 

 ^''G. poliocephala Baird, but larger (the bill especially), upper parts 

 grayer (the tail particularly) , and the edge of the wing and under tail 

 coverts much paler yellow." 



DISTRIBUTION 



Range. — Resident from southern Texas south through Mexico and 

 central Mexico to Panama. One race, the Rio Grande ground-chat 

 {C. p. poliocephala) , is found from southernmost Texas (Harlingen, 

 Lomita, and Brownsville) south to Michoacan (Querendero) Morelos 

 (Cuernavaca) and southern Tamaulipas (Aldama). 



Egff dates. — Texas : 2 records, April 3 and IMay 1. 



