306 BULUETIISr 133, UNITED STATES NATIONAL, MUSEUM 



rapidly for a considerable distance. With its evident predilection 

 for the vicinity of large animals, one may wonder if, hundreds and 

 thousands of years ago, Machetornis was as familiar with the giant 

 ground sloths and glyptodons that ranged then through these same 

 regions as it is now with the stock introduced by man. 



When not in company with cattle, Machetornis frequently ran 

 about on the aquatic plants that covered the surface of small lagoons, 

 where the long legs came in play in enabling the birds to step over 

 interstices between the leaves of the plants. With the coming of 

 September mating activities began, and the flycatchers pursued one 

 another with snap and vigor, uttering high-pitched, squeaky calls 

 and rattling their wings. Occasionally one rested in a tree top to 

 utter a soft song swee see dee^ a low effort that, though simple, was 

 pleasing. 



The Anguete Indians called this bird yeht tin a has goohh. 



MUSCISAXICOLA MACULIROSTRIS d'Orbigny and Lafresnaye 



Muscisaxicola macuUrostris cI'Oebigny and Lafresnaye, Mag. Zool., 1S37, 

 cl. 2, p. 66. (La Paz, Bolivia.) 



The 10 specimens taken were secured as follows: General Roca^ 

 Rio Negro, November 29, 1920, adult female; Zapala, Neuquen, 

 December 8, adult female; Mendoza, Mendoza (altitude, 850 meters), 

 March 13, 1921, male and female; Potrerillos, Mendoza (1,500 to 

 1,800 meters), March 16, IT, 18, and 19, four males and two females. 

 The two adults secured in northern Patagonia in summer are breed- 

 ing birds in slightly worn plumage. The series secured in the Prov- 

 ince of Mendoza are all in fresh fall dress, and may be migrants 

 come from the south. Three specimens seen from Galea, Peru are 

 duller on the abdomen, and grayer on the sides of the head and neck 

 than birds from Argentina, a difference that though slight seems 

 distinct. With specimens from the type locality for comparison, it 

 is probable that two forms may be recognized. 



Following are the dates on which M. mac'lpvostris was recorded: 

 General Roca, Rio Negro, November 29, 1920; Zapala, Neuquen, 

 December 8 ; Mendoza, Mendoza, March 13, 1921 ; Potrerillos, Men- 

 doza, March 15 to 19 ; Tunuyan, Mendoza, March 25. 



Those seen on their breeding grounds were found among low 

 bushes on sandy or gravelly hillsides. Those noted in winter chose 

 similar haunts, usually on sloping flats near streams, or on hill- 

 sides above water, where scattered bushes offered cover but left the 

 ground bare in between. At this season they were found in little 

 parties of two or three that ran alertly about on the ground, or 

 rested for a few minutes in the tops of bushes. Passing insects were 

 secured by a quick spring in the air, while others were picked up 

 in the scanty herbage. Short, low flights, near the ground, revealed 



