FAMILY TYRANNIDAE 393 



tinguished by the dusky chin and yellowish underparts, and also by 

 the darker, more contrasted head pattern. 



There are two slightly different subspecies, as noted beyond, that 

 may be identified only with specimens in the hand. The following 

 summary of occurrence (in considerable part from data supplied by 

 Eugene Eisenmann ) relates to the species as a whole. In fall, by 

 early September, these flycatchers are fairly common. The earliest 

 actual date of arrival is September 8, 1968, when three were seen 

 on the Chiva Chiva road by R. S. Ridgely. Other recent reports from 

 the Canal Zone include September 9. 1962, when one was captured 

 at Albrook Field by Horace Loftin ; September 10, 1968, near 

 Gamboa, by H. M. Stevenson and L. Marsh; and September 27 and 

 30. 1968. on Barro Colorado Island by C. F. Leek. Other reports 

 indicate wide occurrence. George Hicks collected male and female 

 October 5 and 19, 1964, near Almirante, Bocas del Toro. Loftin 

 reports others captured there October 11. 12, and 13, 1963; a male 

 was taken there September 19, 1961, by Tomas Quintero. While most 

 pass in September and October, some may remain later, as Griscom 

 (Bull. Mus. Comp. Zool., vol. 72, 1932, p. 350) reported a male taken 

 by H. von Wedel at Puerto Obaldia, San Bias, November 20, 1930. 



The passage northward begins in March. Eisenmann recorded 

 this species at Panama City, March 12, 1967. A specimen in the 

 American Museum of Natural History was taken by Benson at Santa 

 Fe, Veraguas, March 17, 1925. I have personal records at Los Santos 

 in the Azuero Peninsula for March 15, 1948, on Isla Taboguilla in 

 the Bay of Panama for March 20, 1952, at Charco del Toro on the 

 Rio Maje, eastern Province of Panama, March 24, 1950, and on Isla 

 Cebaco, Golfo de Montijo, March 28, 1962. The birds continue to 

 move through April. 



MYIODYNASTES LUTEIVENTRIS LUTEIVENTRIS Sclater 



Myiodynastes lutcivcntris P. L. Sclater, Proc. Zool. Soc. London, vol. 27, May 

 1859, p. 42. (Verapaz, Guatemala, and Orizaba, Mexico.) 



Characters. — Under surface darker yellow, with the dark streaking 

 broader and heavier ; light markings on back averaging deeper buff ; 

 cinnamon-rufous of upper tail coverts and tail slightly darker. 



Measurements. — Males (10 from Mexico, Guatemala, Honduras, 

 and Costa Rica), wing 112.6-116.6 (114.5), tail 80.0-82.9 (81.7), 

 culmen from base 22.2-25.2 (23.4). tarsus 18.8-20.4 (19.5) mm. 



Females (10 from Mexico, Guatemala, Nicaragua, and Costa 



