FAMILY FORMICARIIDAE 155 



sides and flanks buffy olive ; under wing as in male, except that the 

 inner webs of the secondaries are pale buff. 



These are forest birds, found usually in pairs. When first seen, 

 in form their heavy body and short tail suggest a wren, but their 

 quick action as they move rather quietly among the cover of leaves 

 is more that of a warbler. They range from undergrowth up through 

 the lower tree crown. While they may move about alone, also regu- 

 larly they join the flocks of other small forest birds that travel in 

 mixed company. Often they are timid but again appear a little 

 curious, so that they may come near a human intruder in their haunts 

 with low, chattering calls. 



As a species these small ant-birds range widely from southern 

 Mexico and Guatemala through Central America and South America 

 to northern Argentina, eastern Paraguay, and Brazil. While a num- 

 ber of geographic races have been described these in general differ 

 only slightly in color. Two that are closely similar have been recog- 

 nized in the Republic, one in the east and one in the west. 



DYSITHAMNUS MENTALIS SEPTENTRIONALIS Ridgway 



Dysitharnnus mentalis septentrionalis Ridgway, Proc. Biol. Soc. Washington, 

 vol. 21, October 20, 1908, p. 193. (Choctum, Alta Verapaz, Guatemala.) 



Characters. — Male slightly darker, more grayish, above ; brighter 

 yellow on lower breast and abdomen ; gray on f oreneck and upper 

 breast extending less far posteriorly. Female, averaging somewhat 

 darker above ; brown of crown darker. 



In male and female the iris is very dark brown ; maxilla blackish 

 slate ; mandible neutral gray. 



Measurements. — Males (10 from western Chiriqui), wing 60.2- 

 63.0 (61.5), tail 38.4-43.0 (40.6), culmen from base 16.0-16.8 

 (16.3), tarsus 18.^19.8 (19.3) mm. 



Females (10 from western Chiriqui), wing 58.3-63.0 (60.5), tail 

 38.0-41.4 (39.9). culmen from base 15.7-16.9 (16.3), tarsus 18.7- 

 19.9 (19.3) mm. 



Weight, J* 11 grams, Cerro Campana (G. V. N. Powell). 



Resident. Locally common in more heavily forested areas, mainly 

 in hill country in the upper Tropical Zone. Recorded in western 

 Chiriqui from 750 meters (above Buena Vista) to 1350, less com- 

 monly to 1750 meters, in the area between El Volcan and the Costa 

 Rican boundary, and (by Eisenmann) to 1850 meters above Cerro 

 Punta ; western Bocas del Toro (Rio Changuena, 750 meters) ; east 

 through Calobre, Santa Fe, and Chitra, on the Pacific, and from the 



