232 BULLETIN 133, UNITED STATES NATIONAL MUSEUM 



hill slopes above were little nooks protected from wind and warmed 

 by radiation from the sun-heated stones, to which the hummers re- 

 sorted to rest, and from which they darted down at intervals to feed 

 on the flower clumps below. 



Near Tapia, Tucuman, from April 7 to 13, this species, found as 

 before about the brilliant flower clusters of Psittacanthus, was com- 

 mon. The birds were especially active on days of bright sunshine. 

 Males and females alike poised with vibrating wings in feeding, and 

 at frequent intervals paused to rest on open twigs, usually in the 

 sun as the weather was cool. When three or four gathered at one 

 flower clump there was much fighting among the long-tailed males, 

 while any intruder was greeted with a low chattering call, chit-it, 

 that often came from birds prudently concealed behind the dense 

 shelter of thorny branches. When on the wing both sexes frequently 

 expanded the deeply forked tail, a display, of course, most prominent 

 in the long-tailed males, and males at rest often jerked the tail up 

 and down in gnat-catcher fashion. The flight was rapid and direct, 

 though the bird had the usual hummer habit of swinging up or down 

 with an irregular bounding motion. Because of the long tail it ap- 

 peared large and was easier to folloAv with the eye than most hum- 

 mers. A few were seen near 2,100 meters on the Sierra San Xavier 

 above Tafi Viejo, Tucuman, on April 17. 



A male, taken March 19 above Potrerillos, was molting on the 

 tkroat and had the tail almost grown anew. A male (April 9) and 

 four females (April 8, 9, and 13) from Tapia were in partial molt 

 on head, tail, and body. Immature females differed from the single 

 adult taken in larger green spots on the throat and a wash of cinna- 

 mon on this area. In an adult male when freshly taken the bill 

 and tarsus were black; iris liver brown. 



HELIOMASTER FURCIFER (Shaw) 



Trochilus Furcifer Shaw, Gen. Zool., vol. 8, pt. I, p. 280. (Paraguay.) 



A female taken near Las Palmas, Chaco, on July 31, 1920, 

 like other hummers seen here (in winter) was found near the border 

 of forest, in a region protected from cold winds. The bird, attracted 

 by squeaking, alighted with a subdued humming of its wings on a 

 limb near at hand. 



The bill, tarsus, and toes, in life, were black. 



Family MICROPODIDAE 



MICRCPUS ANDECOLUS DINELLII (Hartert) 



Apus andecolus dinellii Hartert, Bull. Brit. Orn. Club, vol. 23, December 

 31, 1908, p. 43. (Angosta Percliela, altitude 2,550 meters, Jujuy, 

 Argentina. ) 



Dinelli's swift was recorded first in the valley of the Rio Negro 

 soutli of General Roca, Rio Negro, on November 27, 1920, when 10 



