FAMILY FORMICARIIDAE I79 



beginning its search for food. One in the Gorgas Memorial Labora- 

 tory was taken on the Rio Mono, Darien, in January 1969. 



In the stomach of the male taken by Goldman on Cerro Pirre I 

 found remains of spiders, bits of a lygaeid, a homopteran, a chryso- 

 melid and other coleoptera not identified, and remains of earwigs. 



Specimens of this race taken by M. A. Carriker, Jr., in north- 

 western Colombia, include a male from Socarre on the Rio Sinu in 

 the Department of Cordoba, and another from Santa Rosa, near 

 the Rio Magdalena, in the southern Department of Bolivar. 



MICRORHOPIAS QUIXENSIS (Cornalia) : Dotted-winged 

 Ant-wren, Hormiguerito Alipunteado 



Thamnophilus quixensis E. Cornalia, Vertebratorum Syn. Mus. Mediolanense 

 extentium (Osculati coll.), 1849, pp. 6, 12. (Quixos:=Rio Quijos, eastern 

 Ecuador.) 



A small ant-wren, with tail nearly as long as wing ; male black, 

 with wing barred and spotted with white ; female, above like male, 

 under surface cinnamon-brown to chestnut. 



Description. — Length 100-110 mm ; with large white patch on back, 

 concealed by dark feather tips. Adult male, black, usually with sides 

 and flanks slate gray ; center of back broadly white, concealed by the 

 black tips of the long feathers ; lesser and middle wing coverts spotted 

 with white ; greater coverts broadly tipped with white, to make a 

 prominent wing band ; tail tipped with white ; axillars, under wing 

 coverts, and inner margins of wing feathers white ; in some the lateral 

 feathers of the breast, and occasionally the sides with narrow, con- 

 cealed shaft lines of pure white. 



Adult female, upper surface, wings and tail like male, but usually 

 more grayish black, especially on the crown ; under surface cinnamon- 

 rufous to chestnut ; under wing coverts and edgings of primaries 

 white. 



Juvenile, sooty black above ; wing and tail markings reduced in 

 extent ; under surface in male brownish black ; in female dull rufous 

 with a sooty wash, especially on the sides. 



When the wing is fully grown in the immature male, the tips of 

 the secondaries are dotted with white, a marking that tends to 

 disappear with wear as the bird becomes older. 



The species is one of extensive range on the Caribbean slope from 

 southern Mexico through Central America to Costa Rica, and then 

 on both Pacific and Atlantic sides through Panama ; in South America 

 in the west from Colombia (east to the middle Magdalena Valley 



