608 SWALLOW TRIBE. 



the nest. In rocky countries they often take possession 

 of the clefts on the banks of rivers for their dwellincr, and 

 sometimes they content themselves with the holes of 

 trees. 



Their voice is only a low mutter ; and, while busily pass- 

 ing backwards and forwards in the air around their nume- 

 rous burrows, they seem at a distance almost similar to 

 hiving bees. As they arrive earlier than other species, 

 the cold and unsettled weather often drives them for 

 refuge into their holes, where they cluster together for 

 warmth, and have thus been found almost reduced to a 

 state of torpidity. Dwelling thus shut up, they are often 

 troubled with swarms of infestinsf insects, resemblincr 

 fleas, which assemble in great numbers around their 

 holes. They begin to depart to the South from the close 

 of September to the middle of October. Although they 

 avoid dwelling near houses, they do not fly from settled 

 vicinities ; and parties of 6 or more, several miles from 

 their nests, have been seen skimming through the streets 

 of adjacent villages in the province of Normandy. 



In the United States, they are known to breed from 

 Georgia to Maine, and were seen by Lewis and Clarke 

 near the coasts of the Pacific. They are also equally 

 common to Europe and South Africa, and Aristotle re- 

 lates that they were numerous in the narrow pass of the 

 mountains in Greece. 



The Bank Swallow is 5 inches long, and 10 in alar stretch. Tail 

 forked, the outer feather slightly edged with whitish. Wings and 

 tail darker than the body. 



SWIFTS. (Cypselus. Illig,) 



In these birds the bill is extremely short, triangular, cleft to the 

 eyes, depressed, the upper mandible slightly notched and curved at 

 the point. Nostrils lateral, contiguous, large, partly covered by a 

 membrane, leaving a small tubular aperture. Tongue short, wide, 



