272 BULLETIN 133, UNITED STATES NATIONAL MUSEUM 



tion of brush. Their flight was rapid and tilting with the black 

 tail showing prominently as they darted away. The song is a 

 musical, even trill, resembling the syllables tree-ee-ee-ee-ee. On 

 November 24 I found a nest of this species, one of the prominent 

 structures made of sticks so abundant in the brush of this region. 

 The nest, placed in the top of a bush 3 feet from the ground, with- 

 out concealment, was an irregular ball, approximately 400 mm. in 

 outside diameter, constructed of thorny twigs from 100 to 300 mm. 

 long, ranging in size from fine sticks to those as large in diameter 

 as a lead pencil. A tubular entrance tunnel, made of small, very 

 thorny twigs, closely and firmly interlaced, led out at one side for a 

 distance of 400 mm., supported by a limb that grew out beneath the 

 nest. The nest ball was so compactly made that it required some 

 time and trouble to open it. The inner cavity was 125 mm. in 

 diameter and had in the bottom a firmly felted cup of plant down, 

 fur of the introduced hare (common in this region), and feathers. 

 Three eggs that lay on this soft bed, dull white in color, were on the 

 point of hatching and were badly broken in preparation. Two that 

 are more or less entire offer the following measurements, in milli- 

 meters: 20.9 by 15.1 and 20.1 by 14.5. 



SIPTORNIS HUMICOLA (Kittlitz) 



Synnalaxis humicola Kittlitz, Mem. Acad. Imp. Sci. St.- P6tersbourg, Div, 

 Sav., vol. 1, 1831, p. 185. (Valparaiso.), 



Near Concon, Chile, where /Siptornis humicola was fairly common, 

 skins of two males were preserved on April 26 and 27 and a female 

 on April 28, 1921. The birds frequented dense thickets of low 

 brush that grew over the slopes of rolling hills, where they worked 

 slowly about among the limbs or occasionally on the ground, where it 

 was open but heavily protected above. In actions they suggested 

 Synallaxis f. frontalis. Usually they were silent and so were diffi- 

 cult to find, but on one encounter one burst out in a clear, trilled 

 song like that of some wren. The muscular part of the stomach in 

 this species is large and strong, heavier, in fact, in proportion to the 

 size of the bird than in some seed-eating finches. 



A male, when first taken, had the maxilla and tip of the mandible 

 black; base of mandible gray number 8; tarsus, deep olive gray; 

 toes, tea green; iris, natal brown. 



SIPTORNIS LILLOI Oustalet 



Siptornis Lilloi, Oustalet, Bull. Mus. Hist. Nat. (Paris), vol. 10, 1904, 

 p. 44. (Lagunita, Tucuman.) 



An immature female, shot at an altitude of 2,300 meters on the 

 Sierra San Xavier, above Tafi Viejo, Tucuman, was the only one 

 of these birds seen. The specimen is in the immature stage de- 



