Islands of the Coast of Yucatan, S^c. 367 



s- 119. ChjEtura gaumeri. 



Chatura gaumeri, Lawr. Ann. New York Ac. Sc. ii. p. 246. 



Chaetura yucatanica, Lawr. loc. cit. iii. p. 156 (?). 



Cozumel I. (April). 



Many specimens^ varying from 3*9 inclies to 4'6 in the 

 length of the wing. 



Mr. Lawrence has described a second species of Chottura, 

 allied to his C. gaumeri, under the name of C yucatanica, its 

 differences being stated to consist in its smaller size (wing 

 3"9 instead of 4!'25), more ashy throat, darker abdomen, 

 blacker tail, and more tapering tail-feathers. 



It appears from the series before me that the recorded 

 measurements of C gaumeri and C. yucatanica completely 

 overlap ; and as there is some diversity in the coloration, 

 I feel doubtful whether there are really two species in 

 Yucatan distinct from one another and from C vauxi. 



Regarding the latter species, Mr. Lawrence refers a speci- 

 men shot by me near Dueuas on February 6, 1860, and sent 

 ';o the Smithsonian Institution as C vauxi, to his C. gaumeri. 

 Eut two specimens before me, shot at the same place and on 

 ttie same afternoon out of the same flock, seem to me to be 

 ii separable from C. vauxi, of which I have several specimens 

 before me so named by ]Mr. Heushaw. These are generally 

 larger than the Cozumel bird, and not nearly so dark on the 

 abdomen. 



The extent to which the spines of the tail-feathers are 

 ■worn in our series of C. gaumeri varies very much. In some 

 they are long and perfect, in others worn to the webs of the 

 fea-Jiers, so that no specific character can be drawn from this 

 source. 



In our collection we have a specimen from Chiriqui dif- 

 fering in no way from the Cozumel birds, showing that this 

 Swift has really a very wide range. 



-f-120. CHiETURA PELAGICA. 



Chatura pelagica (Linn.) ; Baird, Brew., & Ridgw. N. Am. 

 B. ii. p. 432. 



Cozumel I. (April). 



