THE GENUS CHOBDEILES SWAINSON OBEBHOLSEB. 



67 



and Chordeiles virginianus howelli, being lighter and less ochraceous 

 above, but, so far as we can determine from a single individual, it is 

 nearer the former. Two specimens from Paisano, in central western 

 Texas (Nos. 140404 and 140405, U.S.N.M.), taken, July 14, 1890, by 

 Mr. William Lloyd, are less ochraceous above than even New Mexico 

 birds, in this respect like Ckordeiles virginianus howelli, but they are, 

 nevertheless, dark like Chordeiles virginianus henryi; in size they are 

 rather small, verging in this respect toward Ghordeiles virginianus 

 asernensis; ^ they seem, however, all things considered, to be properly 

 referable to Ghordeiles v. henryi, as they are much too dark and also 

 too large for Chordeiles virginianus aserriensis. This identification 

 is strengthened by two other specimens — one from Fort Stockton, 

 western Texas (No. 43532, M.C.Z.) , taken, May 24, 1860 ; and the other 

 from the crossing of the Pecos Eiver, near the mouth of Delaware 

 Creek, in southern New Mexico (No. 17607, M.C.Z.) , taken, June 11, 

 1855, both of which are seen to be much like typical Chordeiles vir- 

 ginianus henryi. 



The amount of variation in size among specimens of this subspecies 

 from various parts of its range are illustrated in the subjoined table 

 of average millimeter measurements : 



Localities. 



Tail. 



Exposed 

 culmen. 



Tarsus. 



Middle 

 toe. 



Six males, from Arizona 



Five males, from New Mexico 



One male, from western Texas 



Five females, from Arizona 



Four females, from Chihualiua, Mexico 



Three females, from New Mexico 



Three females, from western Texas and southeastern 

 New Mexico , 



mm. 

 198.8 

 200.8 

 193 



187.2 



191 



191.3 



mm. 

 110.6 

 111.8 

 105 



107.8 

 112.3 

 110.7 



108.3 



Tnm. 

 7 



7.1 

 7 



a. 5 

 6.8 

 6.5 



mm. 

 14.5 

 14.8 

 14.1 



13.9 

 14.3 

 14.1 



14.9 

 16.1 

 14.2 



14.6 

 14.8 

 14.9 



13.7 



A specimen of this race from Guadalajara, Jalisco, indicates that 

 it migrates through Mexico on its way to and from its probable 

 winter home in South Amierica. There are records of Chordeiles 

 virginianus " henryi " from Jerez, Zacatecas, Mexico ; ^ Southern 

 Pine Eidge, British Honduras;^ Bogota, Colombia;^ and South 

 America down to Chupat, Patagonia ; ^ but there is, in the absence of 

 specimens, no means of determining to which one of the five western 

 subspecies these records belong. 



This subspecies breeds at about the same time of year as the more 

 northern races; and there are eggs in the United States National 



1 See p. 71. 



2 Hartert, Cat. Birds Brit. Mus., vol. IG, 1882, p. 613. 



3 Idem, p. 612. 



