BIRDS OF ARGENTINA, PARAGUAY, URUGUAY, AND CHILE 257 

 LEPTASTHENURA AEGITHALOiDES AEGITHALOIDES (Kittlitz) 



Synnalaxis Aegithalo'ides Kittlitz, Mem. Acad. Imp. Sci. St.-Petersbourg, 

 Div. Sav., vol. 1, 1831, p. 187. (Valparaiso.) 



Near Concon, in the Intendencia of Valparaiso, Chile, where this 

 bird was fairly common from April 24 to 28, 1921, a male was se- 

 cured on April 24 and three females on April 24, 26, and 27. As 

 Kittlitz remarks that he secured his specimens " auf dem Hohen um 

 Valparaiso," these may be considered as topotypical specimens. The 

 present species is distinguished from L. platensis by somewhat more 

 bushy crest, darker coloration, and grayish white on the inner webs 

 of the rectrices. The genus Leptasthenura^ of which aegithalo'ides of 

 Kittlitz is the type, is distinguished among the Synallaxis group by 

 the possession of a long, slender gi'aduated tail of 12 rectrices and a 

 more or less developed crest. The head feathers in certain other 

 species are often full and long, but are kept closely appressed to the 

 head. In Leptasthenura the development of the crest is observed at 

 once when birds are handled in the flesh, though in the dried skin 

 it is sometimes difficult to distinguish. 



Near Concon, L. aegithaJoldes was encountered, often in company 

 with other small brush-inhabiting birds, in open thickets of low 

 growth that covered the slopes of rolling hills, or in growths of 

 weeds and thorny shrubs near water. The birds clambered about 

 among the limbs, occasionally uttering low complaining notes, in 

 actions resembling titmice. They were gregarious and were not 

 seen alone. The long, slender tail was a prominent character that 

 served to identify them as they passed with tilting flight across 

 small openings between clumps of trees. 



A female, taken April 24, had the maxilla and tip of the man- 

 dible dull black; base of mandible dusky green gray; iris natal 

 brown ; tarsus and toes dull black. 



LEPTASTHENURA AEGITALOIDES PALLIDA Dabbene 



Leptasthenura aegithalo'ides pallida Dabbene, El Hornero, vol. 2. no. 2, 

 January, 1921, p. 135. (Puesto Burro, Maiten. Chubut. alt. 700 

 meters. ) 



The present form is similar to L. a. aegithalo'ides of Chile, but 

 is easily distinguished by its general paler coloration. On Decem- 

 ber 3, 1920, near General Roca, Rio Negro, I found two of these 

 birds resting in the sun in the tops of thick bushes in a region where 

 the atriplex and other growth typical of alkaline flats was tall and 

 dense. The birds rested quietly with long tails hanging straight 

 down, at intervals uttering a low buzzing trill very similar to the 

 songs of some Synallaxis. I was surprised to find that the bird 

 taken, secured during the act of singing, was a female. When fresh 



