338 BULLETIN 133, UNITED STATES NATIONAL MUSEUM 



Tniiuyan, Mendoza, March 26 to 28. It is migrant and retreats 

 northward in winter. 



These birds were found at the borders of groves where they sought 

 commanding perches and watched for passing insects. Tliey were 

 stolid and inactive save when in alert pursuit of prey. Occasionally 

 one uttered a high-pitched, trilling call, and a wing-tipped bird 

 gave staccato cries like those of otlier kingbirds, but ordinarily they 

 were silent. When not hurried, their flight was of the fluttering 

 type, common to other kingbirds, performed with short, rapid vibra- 

 tions of the partly opened wings. 



The two summer skins preserved, in Avorn breeding plumage, in 

 appearance are much darker than those secured in spring. One 

 from Victorica in particular shows little greenish wash on the upper 

 surface. A male, shot December 23, had the bill, tarsus, and toes 

 black; iris natal brown. 



The Anguete Indians in the Paraguayan Chaco called this species 

 Ta pah. 



MUSCIVORA TYRANNUS (Linnaeus) 



MuHcicuim Tyrannus Linnaeus, Syst. Nat., ed. 12, vol. 1, 1766, p. 325. 

 (Cayenne.) 



Specimens of the fork-tailed flycatcher from Argentina appear 

 somewhat darker on the back than the average of those from north- 

 ern South America, Northern and southern forms niaj' not be 

 separated with certainty on the basis of material at hand, as dark 

 birds occur in the north in the small series seen. The (piestion is 

 complicated by the extensive northward migration of the species 

 from temperate areas into the Tropics, 



The species was widespread from spring until fall, and Avas 

 noted as follows: Kilometer 80, Avest of Puerto Pinasco, Paraguay, 

 September 6 to 27, 1920; Dolores, Buenos Aires, October 21; La- 

 valle, Buenos Aires, October 25 to NoA^ember 15; Santo Domingo, 

 Buenos Aires, November 16; General Roca, Rio Negro, November 

 30; Carhue, Buenos Aires, December 17; Victorica, Pampa, De- 

 cember 23 to 28; Carrasco, Uruguay, January 9 and 16, 1921; La 

 Paloma, Uruguay, January 23; San Vicente, Uruguay, January 

 25 to February 2; Lazcano, Uruguay, February 3 to 9; Rio Negro, 

 Uruguay, February 14 to 19; Franklin, Buenos Aires, March 11. 

 The three adult males and one female taken (Kilometer 80, Avest of 

 Puerto Pinasco, Paraguay, September 9, Carhue, Buenos Aires, 

 December 17, Victorica, Pampa, December 28, and San Vicente, 

 Uruguay, January 30) offer no striking peculiarities. Two fe- 

 males in juA^enal plumage shot near Victorica, Pampa, December 

 28, are recently from the nest and have no suggestion of the long 

 tail found in adults. 



