126 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY. 



farther south, on the boundary between Nicaragua and Honduras, is fully 

 as large as the birds from Yucatan. It is rather hazardous to place much 

 dependence upon size in parrots, but since I have not had opportunity to com- 

 pare ray specimens in other respects with undoubted typical albifrons from 

 farther north in Mexico, I have adopted the new subspecific name for the 

 Yucatan birds. It seems not unlikely that the species averages smaller and 

 more yellowish to the southward, though this condition is apparently not 

 limited to the Yucatan peninsula. A. albifrons saltuensis Nelson is distinctly 

 different from any other representatives of the species I have had opportunity 

 to examine. 



MOMOTIDAE. 



36. *Eumomota superciliaris (Swainson). 



Red-backed Motmot. 

 Maya name, toll. 

 Two specimens : 



a. £, Feb. 19, 1904. 



b. £, March 14, 1904. 



These beautiful birds were common, especially about the Sacred Cenote and 

 some of the ancient ruins, particularly the House of the Nuns and the adjacent 

 buildings, where they roosted in the holes in the masonry. At one time sev- 

 eral were brought to me alive which had been easily captured in these holes. 

 The time of my visit appeared to be before the nesting season ; nevertheless 

 the birds were at times very noisy, their note, which is suggested by the Maya 

 name, being a characteristic sound for the Yucatan forest. Besides the repeti- 

 tion of the single note toll (or hvau, as I have it represented in my notes — 

 the au having the sound of a in awl) they sometimes give a series of notes — 

 kwau-ka-wa', kwau-ka-wa', kwau-ka-wa' — which also has more or less variation. 1 

 They fly with small undulations. 



CAPRIMULGIDAB. 



37- Chordeiles acutipennis texensis (Lawrence). 



Texan Nighthawk. 

 One specimen: £, April 2, 1904. 



This bird has been taken at a number of places in Yucatan, but has not 

 previously been reported from Chichen-Itza. 



1 Mr. Thompson says he has recently heard another note of the Motmot — a 

 low, semi-musical series of four notes. The Indians told him it was the ttih that 

 made these notes, but he did not think it could be until he later verified the matter 

 for himself. Sept. 24, 1905. 



