264 BULLETIN 133, UNITED STATES NATIONAL MUSEUM 



SIPTORNIS MALUROIDES (d'Orbigny and Lafresnaye) 



Synallaxis maluroides cI'Orbigny and Lafresnaye, Mag. Zool., 1837, p. 22. 

 (Buenos Aires.) 



S. maluroides is a bird of local distribution in the marshes of 

 Argentina and Uruguay, and extends north along the coast into 

 Eio Grande do Sul. It is often difficult to find and I met with it 

 personally at only three localities. On October 25, 1920, I found it 

 common in growths of rushes in the tidal marshes near the mouth 

 of the Rio Ajo, and collected two males and two females. Super- 

 ficially the birds resemble marsh wrens in appearance and in choice 

 of habit, and, save for their long tails, might easily be confused 

 with Cistothorus. Occasionally they were observed on the ground 

 searching for food near clumps of grass but more often were en- 

 countered only in the heavier growths of Juncus. When startled 

 they flew with tilting flight low over the grass, often blown about 

 in the stiff breeze that swept the marshes. In alighting they some- 

 times perched for a short space with the head projecting above 

 the grass cover so that they were able to look about though their 

 bodies were entirely concealed. Like related species they were 

 usually frightened by the squeaking noise attractive to most small 

 oscinine birds and either flew to some safe retreat or hid in the 

 densest cover available. Females taken were about to lay. On a 

 second visit on November 15 I found these curious birds again 

 common and secured another specimen that was preserved as a 

 skeleton. 



On February 7, 1921, an adult male maluroides was secured in 

 a fresh- water swamp in the valley of the Rio Cebollati, near 

 Lazcano, Uruguay. This bird was molting the feathers of wings and 

 tail. An immature male secured in the rushes of a cienaga near 

 Tunuyan, Mendoza, on March 26, is in full juvenal plumage. 



Adults from Buenos Aires, when compared with the single speci- 

 men from Uruguay, show no appreciable differences, though it is 

 possible that Uruguayan specimens may have larger bills. The 

 bird in immature plumage from Tunuyan has the anterior portion 

 of the crown slightly duller than dark olive buff, with only one or 

 two incoming feathers to suggest the rufescent crown of the adult. 

 The tail is also duller in color than in birds in full plumage. 

 Adult females have the crown patch slightly paler than males 

 though the distinction here is slight. 



SIPTORNIS SULPHURIFERA (Burmeister) 



Spnallaxis sulphurifera Burmeister, Proc. Zool. Soc. London, 1868, p. 

 636. (Buenos Aires.) 



In the vicinity of the Rio Cebollati near Lazcano, Uruguay, the 

 present species was common from February 5 to 9, 1921, in marshes 



