256 BIRDS OF PENNSYLVANIA. 



GENUS TACHYCINETA CABAIJSS. 

 Tachycineta bicolor (VIEILL.). 



Tree Swallow ; White-bellied Swallow. 



DESCRIPTION (Plate 38). 



Length about 6 inches ; extent about 13 inches ; tail slightly forked ; bill black ; 

 legs and iris brown ; lores black; above glossy metallic-green ; wings and tail black- 

 ish, with faint greenish gloss ; lower parts entirely white. 



Young, colors are duller and toes somewhat yellowish. 



Habitat. North America at large, from the Fur countries southward, in winter, to 

 the West Indies and Central America. 



The Tree Swallow, when flying or at rest, can easily be distinguished 

 from all other of our swallows by its dark-colored back and pure white 

 under parts. This species arrives here late in March or early in April, 

 and leaves in September. Common and very generally distributed 

 during- migrations ; as a summer resident seems to be most frequent 

 about rivers and other large bodies of water. From numerous reports 

 before me it is learned that this swallow breeds more or less regularly 

 and rather sparingly in nearly every county in the state. Referring to this 

 bird in Lycoming county, my friend Prof. A. Kock writes in a letter of 

 recent date substantially as follows : It used to breed readily in boxes, 

 but not since the sparrow nuisance has been introduced from England. 

 Have observed the female Tree Swallow enter the dry limbs of high trees 

 (buttonwood) on our river islands. Think we have more some years 

 than others. 



GENUS CLIVICOLA FORSTER. 

 Clivicola riparia (LINN.). 



Bank Swallow ; Sand Swallow. 



DESCRIPTION (Plate 90}. 



Smallest of all our swallows; length about 5, extent about 12g inches; bill black ; 

 legs brownish ; iris dark-brown ; tail short and slightly forked ; lower part of tarsus 

 feathered behind ; above grayish-brown ; beneath white, with a broad band across 

 the breast, same color as on back ; wings and tail dark brown. 



Habitat. Northern hemisphere ; in America, south to the West Indies, Central 

 America and northern South America. 



Common summer resident at many points along Delaware, Susque- 

 hanna and other large streams. 



