36 
U. S. P. R. R. EXP. AND SURVEYS—ROUTE TO CALIFORNIA. 
HIRUNDO RUFA, Vieill.—The Barn Swallow. 
Hirundo rufa, Nutt. Orn. vol. I, p. 601. 
Hirundo americana, Wils. Am. Orn. vol. V, pi. 38, figs. 1—2 .—Aud. B. of A. Fol. pi. 173. 
Hirundo rustica, Aun. Oct. vol. I, p. 181, pi. 48. 
Abundant throughout California, New Mexico, and Texas. 
HIRUNDO BICOLOR, Vieill.—The White-bellied Swallow. 
Hirundo bicolor, Vieill. Ois. Am. Sept. vol. I, p. 61, pi. 31. 
Abundant. 
HIRUNDO LUNIFRONS”, Say.—The Cliff Swallow. 
nirundo fulva, Bonap. Am. Orn. vol. I, p. 63, pi. 7, fig. 1.— Aud. B. of A. Oct. vol. I, p. 177, pi. 47 .—Ib. Fol. pi. 68. 
Abundant, building its nest in the cities under the eaves of houses, and in the mountains 
under the shelving rocks. I found it abundant, also, in New Mexico and Texas. This species, 
formerly considered as one of our western birds, has within a few years commenced its 
migrations to our northern States, gradually extending them year after year further south, until 
it has become in Pennsylvania a regular visitor, like the other common species of the same genus, 
arriving in spring, incubating, and taking its departure in the fall for more genial climes. 
HIRUNDO THALASSINA, Swains.—Violet G-reen Swallow. 
Hirundo thalassina, Sw. Philos. Mag. 1827, p. 366.— Aud. B. of A. Oct. vol. I, p. 186, pi. 49.— Ib. Fol. pi. 335. 
Baird, Gen. Rep. IX. 
I met with this beautiful little species occasionally during our survey, but always on its 
migrations southward, it being the fall of the year. On the summit of the Tejon Pass I shot 
several towards dusk as they flew circling in the air in pursuit of insects, a manoeuvre which 
they are in the habit of performing at this season every evening before retiring to rest. Among 
these large flocks of swallows I remarked a small black swift, (Acanthylis ,) but was unable to 
procure it. While visiting Dr. T. C. Henry, U. S. A., at Fort Thorne, New Mexico, we observed 
many of these swallows flying over a pond on the edge of the Rio Grande river. Its migrations 
extend over California, and it is one of the most abundant species in Oregon. 
COTYLE RIPARIA, L i n n.—The Bank Swallow. 
Hirundo riparia, Wils. Am. Orn. vol. V, p. 46, pi. 38, fig. 4.— Add. B. of A. Oct. vol. I, p. 187, pi 50. 
Abundant. 
COTYLE SERRIPENNIS, Aud.—Rough-winged Swallow. 
Hirundo serripennis, Aud. Synopsis, p. 37.— Ib. B. of A. Oct. vol. I, p. 193, pi. 51.— Ib. Orn. Biog. vol. IV, p.593.— 
Baird, Gen. Rep. IX. 
Abundant. I observed while in Texas, in this species, a curious instance of the manner in 
which birds accommodate themselves to the localities in which they sojourn. The river banks, 
a favorite resort with them around San Antonio, possess in few spots only the conditions requisite 
for their nidification, being either insufficiently steep to afford them opportunities of sinking 
their holes, or being in their more abrupt parts composed of a hard rocky earth, into which they 
