78 BULLETIN 50, UNITED STATES NATIONAL MUSEUM. 



(1) Inner webs of rectrices with a white spot. (Styles a, h, c, d, 

 and/".) 



(2) Rump glossy black, like back, etc. (Styles a, b, and c.) 



(3) Rump chestnut, rufous, or cinnamon-buffy. (Styles d, e, and/.)' 



(4) Forehead chestnut, the rest of pileum together with auricular 

 region black. (Styles a, h, and c.) 



(5) Entire pileum black, the auricular region chestnut, rufous, gray 

 (finely streaked) or whitish. (Styles d and e; the latter divisible into 

 two subgroups, one having the forehead entirely black and no com- 

 plete nuchal collar, the other having the anterior portion of the fore- 

 head more or less rufescent and a complete nuchal collar of rufous.) 



(6) Entire pileum rufous. (Style/.) 



Nidification. — Nest cup-shaped (open above), composed of mud- 

 pellets, attached to face of rocks or parts of buildings (usually inside), 

 lined with soft feathers; eggs spotted. 



Bmige. — Cosmopolitan. 



KEY TO THE SPECIES OF HIRUNDO. 



o. Throat and forehead deep chestnut; pileum and hindneck glossy dark steel blue, 

 like back. (Adults. ) 

 h. Black jugular band very broad, extending uninterruptedly across chest. 

 (Palsearctic region, except extreme eastern portion; migratiug in winter into 

 Indo-Malayan and African regions; accidental in America.) 



Hiruudo rnstica, adults (p. 79) 



hh. Black jugular band narrow and completely interrupted, or else very narrow 



and more or less broken in middle portion. 



c. Under parts of body varying from nearly white to buffy cinnamon-rufous ;o 



adult male averaging wing 119.3, tail 107; adult female, wing 117, tail 87. 



(North America; Mexico, Central America, and most of South America in 



winter.) Hirundo erythrogastra, adults (p. 80) 



cc. Under parts of body varying from cinnamon-rufous to nearly chestnut; 

 adult male averaging wing 118.2, tail 89.1; adult female, wing 115.4, tail 

 76.4. (Eastern Asia, breeding in Kamchatka and eastern Siberia; occa- 

 sional in western North America, Central America, and South America?) 



Hirundo tytleri, adults (p. 82) 

 aa. Throat and forehead pale cinnamon-rufous or vinaceous-rufous. (Young. ) 



6. A broad dusky band across chest Hirundo rnstica, young (p. 79) 



bh. A very narrow, if any, dusky band across chest (usually none, except lat- 

 erally) Hirundo erythrogastra, young (p. 81) 



a The darker males of H. erythrogastra approach so nearly in color of the under 

 parts to females of H. tytleri that I am unable to distinguish them satisfactorily. In 

 fact, two females in the American series (nos. 65482, U. S. Nat. Mus. coll. , Amak- 

 nak Island, Unalaska, June 7, 1873, and 70879, St. Michael, Alaska, June 22, 1876, 

 are equally deep colored beneath, the latter (as well as several of the lighter colored 

 American specimens) having thejugular collar complete, though very narrow, as in 

 H. tytleri, and the frontal chestnut patch even broader than in examples of the latter. 

 It is possible these specimens may be wrongly determined as to sex; if not, I am 

 unable to see how the two forms can be invariably distinguished. 



