In the series in the British Museum there is very little variation in plumage. The measure- 

 ments are as follows : — 



Total length. Wing. Tail. Tarsus. 



in. in. in. in. 



a. $ ad. Mexico (coll. Jard.) 4"8 4'05 T8 0-4 



b. <J ad. „ (De Saussure) 51 4 - 15 T75 045 



c. Ad. „ „ 1-9 4-2 1-7 0-45 



d. Ad. „ (Boucard) 4'8 4-0 17 0-4 



e. Ad. „ {Salle) 5-0 '4-1 T8 CC45 



/. ? ad. Oaxaca (Boucard"} 4"5 4-1 1-8 0"45 



g. Juv. Duefias (Salvin) 4 - 7 4'0 T75 0"4 



h. Juv. Costa Rica 4"0 4-15 17 0'45 



The voung bird differs from the adult in being altogether browner, with no purple gloss, and 

 scarcely any appearance of dorsal streaks ; the rump has a pale rufous band ; the wings and tail 

 are both brown ; crown of head dusky blackish, with a slight blue gloss, the feathers round the 

 hind neck clingy brown ; a slight shade of rufous on the forehead and over the eye ; ear-coverts, 

 sides of face, cheeks, throat, and chest dusky brown, with a slight wash of rufous on the throat ; 

 breast and abdomen white, the flanks and vent washed with pale fulvous brown, the under 

 tail-coverts dusky brown, margined with buffy white. Total length 4\2 inches, wing 4'2, 

 tarsus 0"45. 



Another young bird in the Salvin-G-odman Collection has the rufous portion of the plumage 

 more strongly marked than the one described, and has the brown feathers of the upper surface 

 fringed with reddish brown or whity brown at the ends. 



Hab. Central America, from Mexico to Guatemala. 



In 1827 Swain son described specimens of this Cliff-Swallow, which had been obtained 

 by Bullock on the Tableland of Mexico and at Real del Monte, by the singularly 

 inappropriate name of Hirundo melanogaster, but in his description he does not mention 

 the black colour of the belly as a character. Messrs. Salvia and Godman suggest that 

 the black spot on the throat may have been intended to be referred to by Swainson, but 

 in any case the wrong impression conveyed by the name fully justified Dr. Sclater in 

 altering it to the more appropriate one of sioainsoni. The name of coronata, published 

 by Lichtenstein in a price-list of Mexican birds in 1880, is unaccompanied by any 

 description, and cannot therefore be used. 



Swainson's Cliff-Swallow is nearly allied to the North-American species, P. pyrrho- 

 nota, but is easily distinguished by its chestnut forehead. In this latter character it 

 resembles P.fuloa, but the last-named bird has no black patcli on the lower throat. 



The range of the species has been well summed up by Messrs. Salvin and Godman, 

 whose words we quote from the ' Biologia ' : — " Though P. sioainsoni has been met with 

 by many travellers in Mexico, we have nothing recorded of it beyond certain localities 

 where it occurs. Prof. Sumichrast says it is peculiar to the plateau of Mexico, and that 

 it rarely occurs elsewhere ; still it has been found in the State of Oaxaca, and, even 



