136 BIRDS OF THE REPUBLIC OF PANAMA PART 3 



be noted that in general T. d. pacificiis is closer to T. d. (yucatanicusy 7 

 found in the Yucatan Peninsula in Campeche, Yucatan, and Quintana 

 Roo, ranging south to Peten in northeastern Guatemala and in 

 intermediate form in northern British Honduras. This population in 

 the male has somewhat less white in the crown, and is slightly darker 

 above and below. The female is slightly darker. These two paler 

 populations are separated completely from one another by the de- 

 cidedly darker T. d. intermedins which ranges through eastern and 

 southern Mexico, west of the Yucatan Peninsula and eastern Peten, 

 from eastern Guatemala and Honduras south through eastern Nica- 

 ragua and eastern Costa Rica. 



Near El General, Costa Rica, Skutch (Pac. Coast Avif., no. 35, 

 1969, pp. 192-196) has recorded five nests in or adjacent to thickets 

 where they were placed at varying elevations from a little less than a 

 meter to slightly more than 3 meters above the ground. "Each was a 

 deep, thin-walled, but well made cup attached by its rim to the arms 

 of a horizontal fork." They were constructed of various fibers, 

 usually with bits of green moss on the outside. The eggs were white, 

 marked with spots and lines of chocolate, and purplish brown, often 

 concentrated in a wreath on the larger end and present only sparingly 

 elsewhere. There is much variation in amount and form of markings 

 in this species. The usual set is of two eggs. Skutch recorded 

 measurements in four as 23.8x17.1, 23.8x17.5, 23.0x17.5, and 

 22.6 X 16.7 mm. Both parents shared in incubation, with the female 

 alone during the night, and both fed the young. When hatched the 

 young are without down. 



THAMNOPHILUS DOLIATUS NIGRICRISTATUS Lawrence 



Thamnophilus nigricristatus Lawrence, Proc. Acad. Nat. Sci. Philadelphia, 1865, 

 p. 107. (Lion Hill Station, Panama Railroad, Atlantic slope, Canal Zone, 

 Panama. ) 



Characters. — Male, with crown mainly black (white markings 

 much restricted and in some specimens absent) ; otherwise like 

 pacificus on the upper surface ; under surface decidedly paler, with 

 the central abdomen in many much lighter or even white without bars. 

 Female averaging paler. 



A male, collected January 21. 1962, at Las Palmitas, Los Santos, 

 had the iris yellowish white ; maxilla black ; mandible neutral gray ; 

 tarsus, toes, and claws neutral gray. Another, apparently younger, 

 on January 20, 1963, at Gago, Code, had the iris pale dull yellow ; 

 culmen and distal end of maxilla black; side of maxilla from base, 



