l8o BIRDS OF THE REPUBLIC OF PANAMA PART 3 



and eastern Narino) south through Ecuador, eastern Peru, north- 

 eastern Bolivia, and Brazil south of the Amazon ; and in the east in 

 eastern Surinam, French Guiana, and northeastern Brazil (Amapa). 

 Two subspecies are found in Panama. 



These are mainly forest birds ranging in open forest and forest 

 edge from the undergrowth to the lower tree crown, sometimes singly 

 or in pairs, often with fiocks of other ant-wrens and small birds that 

 travel in company. Usually they are less secretive than the species 

 of Myrmotherula which often are their associates. In color and 

 plumage pattern they are definitely attractive. As they move about 

 they utter low chattering scolding calls, usually higher pitched than 

 those of other small ant-wrens. Occasionally I have heard them give 

 rapid, trilling songs. Often in display males expand the back feathers 

 so that the white, normally concealed, is shown prominently. 



MICRORHOPIAS QUIXENSIS VIRGATA (Lawrence) 



Formicivora virgata Lawrence, Ibis, ser. i, vol. 5, April 1863, p. 182. (Lion 

 Hill, Canal Zone, Panama.) 



Characters. — White tip on outer rectrices 5-7 mm long ; male, with 

 flanks slate color ; female, lighter cinnamon-rufous on the under 

 surface. 



A male taken at Canita, on the lower Rio Bayano, eastern Province 

 of Panama, February 6, 1962, had the iris dark brown ; posterior 

 three-quarters of the cutting edges of maxilla and mandible neutral 

 gray ; rest of bill black ; tarsus and toes dark neutral gray ; claws black. 

 Another male, collected at Puerto Armuelles, Chiriqui, February 22, 

 1966, differed in having the iris reddish brown, and the tarsus, toes, 

 and claws bluish slate. 



A female from Juan Mina, Canal Zone, January 17, 1961, had 

 the iris dark brown ; side of maxilla from base forward to halfway 

 between the nostril and the tip, and the side of the mandible, except 

 the tip, neutral gray; rest of bill black; tarsus, toes, and claws dark 

 neutral gray. One taken at Puerto Armuelles, Chiriqui, February 22, 

 1966, differed in having the iris dark reddish brown, and the claws 

 black. 



Measurements. — Males (10 from western Panama), wing 48.2- 

 51.7 (49.7), tail 41.5-45.5 (43.5), culmen from base 14.2-14.9 

 (14.5), tarsus 15.2-16.0 (15.5) mm. 



Females (10 from western Panama), wing 46.5-49.9 (48.1), tail 

 40.0-44.4 (42.6), culmen from base 13.7-15.6 (14.6), tarsus 15.1- 

 15.9 (15.4) mm. 



