Vol. XV, p. 211 " October 10. 1902 



PROCEEDINGS 



OF THB 



BIOLOGICAL SOCIETY OF WASHINGTON 



ANEW SUBSPECIES OF THE CUBAN CLIFF SWALLOW. 



BY E. W. NELSON. 



The discovery of a subspecies of Petrochelidon fulva occujjy- 

 ing a limited area on the Mexican tableland, remote from the 

 seacoast, between the ranges of P. melanogaster and P. luni- 

 frons, and apparently not intergrading with either, is one of 

 those curious cases of distribution so difficult to understand. 



A similar and even more striking case is the presence in the 

 mountains of Sinaloa of a marten {Progne sinaloce) closely re- 

 lated to P. dominicensis but with its habitat surrounded by the 

 territory occupied by P. subis and P. chalyhea. 



Petrochelidon fulva pallida new subspecies. Coahuila Cliff Swallow. 



Typel^o. 183,703 $ ad., U. S.Nat. Mus., Biological Survey Collection. 

 Saltillo, Coahuila, Mexico, April 17, 1902, E. W. Nelson and E. A. Gold- 

 man. 



Distribution. — Arid border of table-land in northeastern Mexico in por- 

 tions of Coahuila and Nuevo Leon. 



Subspecific Characters. — Similar to P. fulva from which it differs in the 

 slightly larger size and paler colors. The rufous frontlet is only a little 

 paler but the nuchal collar and rump are decidedly paler and more rusty 

 rufous. The wash of reddish on sides and underpartsof head and neck is 

 paler and is usually absent along sides of breast and body. The dark 

 centres of under tail coverts average paler. 

 f Dimensions of type. — Wing, 108; tail, 50; culmen, 7; tarsus, 12. 



Remarks. — The amount of differentiation of this form from the Cuban 

 bird is very slight considering their isolation from one another and the 

 great differences of physical surroundings in the homes of the two forms. 



43— BIOL. SOC. WASH. VOL. XV, 1902. (311) 



