74 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 134 
IRIDOPROCNE ALBILINEA (Lawrence): Mangrove Swallow, 
Golondrina Manglatera 
Petrochelidon albilinea LAwrence, Ann. Lyc. Nat. Hist. New York, vol. 8, May 
1863, p. 2. (Atlantic slope near the Panama Railroad, Canal Zone, Panama.) 
These small swallows, of pleasing color in their contrast of white 
lower surface and rump and steely blue-green head, wings, tail, and 
back, are found always near or over water. On Coiba I recorded 
two January 27 on the flats laid bare by the tide at the mouth of the 
Rio Catival, and February 2 I collected a pair flying over a wet 
meadow at Bajo Espafa. 
A race of the mangrove swallow has been described by van 
Rossem *+ from southern Sonora with range south to Nayarit. I am 
not able to recognize this from the fair series in the National Museum 
and the American Museum of Natural History. The material that 
should represent riizophorae includes seven specimens from southern 
Sinaloa (Mazatlan, Los Lates near Rosario, Escuinapa) and seven 
from near the coast of Nayarit (Tuxpan, San Blas). From Panama, 
the type locality of albilinea, there is a good series, including birds 
collected personally that I know to be breeding, so that with these the 
possibility of migrants from northwestern México is eliminated. 
Three birds from Los Lates near Rosario, Sinaloa, in freshly molted 
dress, are very distinctly greenish above, being equaled in this only 
by a skin in similar stage from Aguadulce, Province of Coclé, 
Panama. As the season advances the dorsal color, through wear, be- 
comes steadily bluer. A pair from the Rio San Pablo, near Sona, 
Veraguas, Panama, that represent the breeding stock of that area, 
are slightly bluer than any I have seen from Sinaloa, so that the dif- 
ference in darker blue of the northern birds, listed by van Rossem, 
does not hold. 
The distinction of greater amount of frontal and loral white pro- 
posed as one of the prominent characters of the northwest Mexican 
race varies decidedly in the Panamanian series, several from the 
latter group being as white as the northern birds, others less so. In 
some the frontal feathers are pure white at the base, this color be- 
coming exposed by wear. Specimens with this character include 
birds shot in Panama December 16, February 2 and 23, May 29, and 
June 2, so all of them could not be considered migrants from the 
north. There is similar individual variation in the rump color, and in 
size of the bill. I am forced to conclude that the population of 
northwestern México may not be separated by name. 
21 [yidoprocne albilinea rhizophorae van Rossem, Proc. Biol. Soc. Washington, 
vol. 52, Oct. 11, 1939, p. 155. (Tobari Bay, Sonora.) 
