374 CYPSELID^. 



Swift at Villa Alta in Oaxaca, but no specimens, so far as we know, were included in 

 MM. Salle's and Boucard's collections. 



Nor have we any tidings of it from any of the more northern or western parts of the 

 Republic of Mexico. 



In Guatemala we believe it to be pretty generally distributed, and we observed it at 

 different places from the sea-level at San Jose de Guatemala to as high as the mountain 

 ridge above Calderas on the Volcan de Fuego, an altitude of 8300 feet. 



In the rainy season flocks of this Swift were frequently to be seen flying high over 

 the plain of Duenas, occasionally descending to within gun-shot, when a few specimens 

 could be secured. A roosting-place of a flock of these birds was in the rocks over 

 which the Guacalate formed a cascade near the village of Ciudad Vieja. On one 

 occasion a number of these birds which had been observed flying over the valley 

 suddenly descended and disappeared behind the fall. 



2. Chsetura semicoUaris. 



Acanthylis semicoUaris, De Sauss. Rev. Zool. 1859, p. 118'. 



Chmtura semicoUaris, Scl. P. Z. S. 1865, p. 609 ^ ; Scl. & Salv. Ex. Orn. p. 103, t. 52 ' ; Sumichrast, 



Mem. Bost. Soc. N. H. i. p. 562*; Herrera, Apuntes de Omit. p. 15 '; Hartert, Cat. Birds 



Brit. Mus. xvi. p. 479 \ 

 Hemiprocne semicoUaris, Sumiclirast, La Nat. v. p. 250 ''. 



Fuliginoso-nigra, capite toto et giitture vix pallidioribus, fascia transversa angusta nuchali alba. Long, tota 

 circa 9-5, alse 9'2, caudse 2"9. (Descr. exempl. typ. ex Mexico. Mus. Brit.) 



Hob. Mexico^, San Joaquin near the capital [Sumichrast'^). 



Several specimens of this large Swift were killed near Mexico city by Sumichrast 

 when he was in company with M. H. de Saussure in 1856 ^. These birds were described 

 by the latter naturalist in 1859 ^, and one of the typical specimens passed into Mr. Sclater's 

 possession and was figured in ' Exotic Ornithology ' ^. This last-named bird, which is 

 now in the British Museum, is the only one we have seen. 



Of the species very little is known ; Sumichrast does not seem to have met with it 

 again, and Herrera speaks of it as probably a bird of accidental occurrence^. Neither 

 Salle nor Boucard notice it ; nor have we any tidings of it in the large collections of 

 Eichardson, Lloyd, and others recently formed in various parts of Mexico. 



C. semicoUaris is most nearly allied to C. zonaris, but may readily be distinguished 

 from that species by its large size and by the white collar being restricted to the back of 

 the neck, and not forming a complete ring round it, as is the case in the allied form. 



b. Minores: torques cervicalis nullus. 



3. Chaetura pelagica. 



Hirundo pelagica, Linn. Syst. Nat. i. p. 192 (1758) \ 



Chatura pelagica, Baird, Brew., & Ridgw. N. Am. Birds, ii. p. 432 ' ; Coues, Birds N. W. p. 267 '; 

 Salv. Ibis, 1889, p. 367*; Hartert, Cat. Birds Brit. Mus. xvi. p. 480'. 



