370 [JUNE, 
lustre, every feather of the head above, back, rump, wing coverts and upper 
tail coverts narrowly edged and tipped with grayish white, nearly obsolete on 
the head in some specimens and on the back in others, but generally so distinct 
as to present a mottled and scaly character. 
Under parts with the sides and flanks brownish black with a green lustre, 
feathers edged with gray as in the plumage of the upper parts. Wide medial 
portion of the entire under parts from tze base of the lower mandible to the tail 
coverts white, in some specimens mixed with brown, especially on the breast. 
Under coverts same as the flanks, and largely marked with white, in some 
specimens with the latter color predominating. Plumage of the tibie and tarsi 
dark brown, claws pale horn color. 
Hab. British Guiana. 
Obs. Specimens of this little species have been presented to the collection of 
the Academy by Henry G. Dalton, M. D., an accomplished and eminent physi- 
cian and naturalist, resident in Georgetown, British Guiana. . He represented it 
as a common bird in that country, and known by the name of Sand Martin, on 
account of its living in holes in the ground in sandy situations. 
We have been rather disappointed in not finding a description of this bird, but 
our impression is that it has been confounded with the Hirundo nigra, Gm., and 
it seems to be the third variety of that species as given in Syst. Nat. 1, p. 1025. 
The true H. nigra, which has been found in Jamaica by Mr. Gosse (B. of Jam. 
p. 63, pl. 10,) is much larger, and is so described by Gmelin. Though resem- 
bling in some measure the species mentioned above, it is easily recognized by 
the scaly character of its plumage, more or less apparent in all the specimens 
that we have seen, and is distinguished from any of its American relatives by 
its very long tail and wings, and small size. 
2. PeTROCHELIDON MURINA, 7obrs. 
Form. Size of P. leucorrhoa (Vieill.) whichis H. frontalis, Gould, and slightly 
larger than Chelidon urbica, (Linn.) Bill, tarsi, and feet small and weak, wings 
rather long, broad, with the second quill slightly longest, tertiaries emarginate, 
tail rather wide, forked. 
Dimensions. Total length (of skin) from tip of bill to end of tail about 5} 
inches, wing 43, tail 25 inches. 
Colors. Entire under parts from the base of the lower mandible, (except the 
inferior tail coverts,) dark cinereous or mouse color with a silky lustre, uni- 
form and unspotted. Under tail coverts brownish black with a green lustre. 
Head above, back, rump, wing coverts and upper tail coverts black witha 
green lustre slightly tinged with violet. Wings and tail brownish black with a 
very slight green lustre. 
Hab. Republic of Ecuador, South America. 
Obs. This bird appears to be allied to Hirundo patagonica and H. andecola, 
D’Orbigny, Guérin’s Magasin, 1837, p. 69, and is about the size of the latter. 
It has, however, no white on any part of the plumage, and the tail is strongly 
forked. 
The only specimen in the museum of the Academy was received in one of the 
very interesting collections presented by its constant friend Edward Wilson, 
Esq., of Pembrokeshire, England, and was obtained by him in Paris. 
3, PETROCHELIDON ? TIBIALIS, zobis. 
Form. Small, size of Cotyle riparia, (Linn.) 
Bill curved, rather strong, wing moderate with the first quill longest, tail 
rather short only slightly forked. 
Dimensions. Total length (of skin) from tip of bill to end of tail about 44 
inches, wing 3 6-10ths, tail 2} inches. 
Colors. Plumage of the tibiae white, other inferior parts entirely smoky 
brown, darkest and nearly black at the ends of the inferior tail coverts. Entire 
upper parts brownish black with a greenish lustre on the head and back, and 
palest on the rump. Wings and tail brownish black. 
Hab. Unknown. 
Obs. This species, of which the sp2cimen described is from the Rivoli collec- 
