FAMILY FORMICARIIDAE 20I 



one will compress the feathers at the sides, so that the white wing 

 edging shows as a prominent line. The bright blue of the small 

 amount of bare skin of the sides of the face then shows prominently 

 in both male and female. Other notes include a low chatter, and a 

 purring call, heard only when they are near at hand. 



They are casual rather than persistent attendants on ant swarms, 

 and also sometimes join briefly little groups of other low bush feeders, 

 as the song wrens. In fact this ant-bird, in its general form, with its 

 heavy body, short tail, and rather long bill, coupled with its secretive 

 habits, may suggest superficial resemblance to the larger wrens. 



The species ranges from the Caribbean lowlands of Nicaragua 

 and on both slopes of Costa Rica south to western Ecuador and 

 northern Colombia. It is a common bird with some diversity in color 

 throughout the Isthmus where four subspecies may be recognized. 

 In Panama I have not recorded them in the savanna areas of the 

 Pacific slope, nor in the lowlands of the eastern side of the Azuero 

 Peninsula. 



MYRMECIZA EXSUL OCCIDENTALIS Cherrie 



Myrmeciza immacidata occidcntalis Cherrie, Auk. vol. 8, no. 2, April 1891, p. 

 191. (Pozo Azul de Pirris, Pacific slope, Province of San Jose, Costa Rica.) 



Characters. — Similar to M. e. exsul, but paler. Male, with head 

 and hindneck slate-black; rest of upper surface chestnut-brown; 

 ventral surface slate-gray with foreneck averaging grayer ; flanks and 

 under tail coverts lighter brown. 



Female, slightly darker brown above than the female of exsul; 

 brigher brown on ventral surface. 



Measurements. — Males (13 from Costa Rica, Chiriqui, and Vera- 

 guas), wing 63.5-69.2 (67.2), tail 44.0-48.8 (46.7), culmen from 

 base 21.4-23.6 (22.3), tarsus 27.7-28.9 (28.4) mm. 



Females (17 from Costa Rica, Chiriqui, and Veraguas), wing 

 62.6-68.0 (64.7), tail 41.2^6.9 (44.6), culmen from base 20.3-22.5 

 (21.4), tarsus 27.0-29.5 (28.2) mm. 



Resident. Found locally on the Pacific slope of Chiriqui and 

 Veraguas, east to the western side of the Azuero Peninsula, from 

 sea level to 600 meters elevation. 



The race ranges north beyond Chiriqui on the Pacific slope of 

 southwestern Costa Rica to the Gulf of Nicoya. 



Fortunately these birds are able to live in the small areas of 

 suitable habitat that remain on steep slopes, in forested ravines, or 

 along the banks of streams, since now these are the main, or only 



