1874.] 53 [Allen. 



21. Setophaga ruticilla Sw. Redstart. 



Quite common along the Missouri at Fort Rice in June, where it 

 •was apparently breeding. Not met with elsewhere. 



A bird supposed to be Dendroeca Auduboni, was seen on two or 

 three occasions (on Davis Creek, and near the mouth of the Big 

 Horn River), but it eluding capture, it was not positively identified. 



HIRUNDINID^. 



22. Hirundo horreorum Bart. Barn Swallow. 

 Occasional pairs met with throughout the district traversed, but it 



was nowhere common. Found it nesting under projecting rocks, 

 against which the nest was plastered. Dr. Hay den has also reported 

 its nesting " on the vertical sides of the bluffs along the Missouri," 1 

 this being its normal mode of nesting doubtless everywhere prior to 

 the occupation of this continent by the whites. 



23. Tachycineta bicolor Cab. White-bellied Swallow. 

 Common at one locality on the Musselshell, but not seen elsewhere. 



24. Tachycineta thalassina Cab. Violet-green Swallow. 

 First seen near the mouth of Tongue river, and frequently on the 



Yellowstone for some distance above this point. 



25. Petrochelidon lunifrons Cab. Cliff' Swallow. 



Rather common. The most numerous and the most generally dis- 

 tributed of the Hirundines. A peculiar deviation from its usual 

 mode of nesting, which was observed at some sandstone bluffs near 

 the Yellowstone Crossing,- seems worthy of note. The sandstone had 

 weathered in such a manner as to leave the face of the bluff full of 

 rounded cavities a few inches in diameter. Here a large colony of 

 these swallows, instead of affixing their nests against the smooth face 

 of the cliff, as they usually do, built them in these weatherworn 

 holes. A few nests were built in the ordinary way, but most of them 

 were formed by adding a neck to the holes already existing in the 

 rocks ! Some of them looked like nests imbedded in the cliff', with 

 only the neck of the retort-shaped structure projecting. On another 

 occasion I had an opportunity to note the breeding of this species in 

 holes in banks, in the same manner as, and in company with, a large 

 colony of sand martins. 2 At Fort Rice a colony had taken possession 



1 Trans. Am. Phil. Soc, xn, p. 161. 



2 Bull. Mus. Comp. Zool., Vol. in, p. 125. 



