BIRDS OF ARGENTINA, PARAGUAY, URUGUAY, AND CHILE 291 



bonariensis) . The two white eggs measure, respectively, in milli- 

 meters, 24.5 by 18.3 and 27.3 by 20.5. The smaller egg has a glossier, 

 more irregular surface than the large one, which is smoother and 

 dull in color. The difference in size and appearance between the 

 two is so striking that I believe that the larger egg alone is that of 

 RMnocryfta^ and that the smaller one was deposited in the nest by 

 some Synallaods. The parent {R. lanceolata) slipped down from 

 the nest through the branches to the ground; when secured, to my 

 surprise, it was a male. 



Near Mendoza, Mendoza, this species was fairly common on March 

 13, 1921, but was very shy. At Potrerillos, Mendoza, it was recorded 

 on March 17, and several were seen and a female taken at El Salto, at 

 an elevation of 1,800 meters. Others were recorded on March 27 

 below Tunuyan, Mendoza, through a low range of sandy hills east of 

 the Rio Tunuyan. In fall the birds were much shyer than during the 

 breeding season, and, though their notes were heard, it was only by 

 chance that one was seen as it ran across some little opening in the 

 brush. Usually they took care to edge aside without exposing them- 

 selves. The fall specimen secured is brighter, bufRer brown above 

 and on the flanks and under tail coverts than summer birds, 

 but is otherwise similar. The difference in color is attributed to the 

 fact that this bird is in fresh fall plumage, while the others are some- 

 what worn. 



An adult male, taken November 27, had the maxilla and tip of 

 mandible dull black ; base of mandible, neutral gray ; iris, Vandyke 

 brown; tarsus and toes, black. 



TELEDROMAS FUSCUS (Sclater and Salvin) 



Rhinocrypta fusca Sclateb and Salvin, Nom. Av. Neotr., 1873, p. 161. 

 ( Mendoza. ) 



Near General Roca, Rio Negro, the barrancolino, as this tapaculo 

 is known, was fairly common from November 25 to December 2. 

 1920. Adult males, preserved as skins, were taken on November 25 

 and 26, and a female on November 26. The species was found in 

 low, open brush over the dry gravel hills that bordered the level 

 valley of the Rio Negro, in a region wholly without permanent 

 water. As I passed along the shallow, steep-walled barrancas that 

 traversed this area, I had an occasional glimpse of a wrenlike bird 

 of moderate size, as, with tail cocked over its back, it sprinted away 

 over open ground, swerving constantly behind low clumps of vege- 

 tation for protection. Like snowy plover the birds ran on and on 

 and on long after one might expect them to stop, and hard running 

 was required on the part of the collector in order to keep up with 

 them. At other times as I cared for specimens that I had shot one 



