72 BULLETIN 86, UNITED STATES NATIONAL MUSEUM. 



paler, more brownish above, with markings more tawny or ochra- 

 ceoiis. She may be differentiated from the female of Chordeiles vir- 

 ginianus hoioelli by her lighter, less brownish (more grayish) upper 

 surface, with less tawny and ochraceous in the light markings; and 

 by the less deeply buffy lower parts. 



No Juvenal or first autumn specimen of Chordeiles virginicmus 

 aserriensis has been available, but in this plumage this race is doubt- 

 less similar to that of Chordeiles virginianus hoioelli^ though more 

 grayish; that is, intermediate in color between the latter form and 

 Chordeiles virginianus sennetti. 



Individual variation has about the same range as in other races, 

 though greater than in some. In the male the posterior lower parts 

 are usually almost pure white, occasionally washed with buff; the 

 breast and jugulum dark brown, varying to a much lighter shade, 

 which is still further lightened by being much obscured by large 

 buff and cream buff spots. The upper surface of the male is in color 

 normally somewhere between Chordeiles virginianus sennetti and 

 Cho7'deiles virginianus howelli, but rather lighter than either. From 

 this it varies to (1) a much more brownish shade, with buffy ochra- 

 ceous markings, so that it is practically like Chordeiles virginianus 

 howelli, as in No. 81582, American Museum of Natural History, 

 Corpus Christi, Texas, April 24, 1889; to (2) a still lighter brown, 

 which is more heavily light-mottled, as in No. 152229, U.S.N.M., San 

 Antonio, Texas, May 9, 1891 ; to (3) a very grayish and blackish con- 

 dition, with the light mottlings somewhat reduced, so that it becomes 

 almost like Chordeiles virginianus sennetti^ as in No. 27307, Acad. 

 Nat. Sci. Phila., Corpus Christi, Texas, May 23, 1891 ; and to (4) a 

 condition like the last, but with the light mottlings much reduced, so 

 that the general tone is much more blackish — almost identical with 

 typical Chordeiles virginianus hesperis^ as in No. 203649, U.S.N.M., 

 Eunge, Texas, September 21, 1906. These variations are, of course, 

 exceptional ; and Chordeiles virginianus aserriensis is so much smaller 

 than any of the races that it closely resembles in color that there 

 should usually be no difficulty in identifying specimens. Some such 

 individuals as (3) have been identified as Chordeiles virginianus 

 '■'■sennettiy'' and the so-called Texas " type " of Chordeiles virginianus 

 sennetti has been found to be one of these. In the female the ground 

 color of the posterior lower surface ranges from buffy white to deep 

 buff, and averages about cream buff. The upper parts vary about as 

 in the male: To (1) a light brown with ochraceous mottling, very 

 much like the same sex of Chordeiles virginianus howelli, as in No. 

 19853, Carnegie Museum, Cameron County, Texas, May 16, 1902; to 

 (2) a similar light brown, more heavily mottled, but with less ochra- 

 ceous, as in No. 197786, U.S.N.M., Eunge, Texas, August 25, 1905 ; and 

 to (3) a very dark, blackish brown, with much reduced light mark- 



