so BULLETIN" 86, UNITED STATES NATIONAL MUSEUM. 



grayish, buffy or ochraceous; and of the width of the dark bars on 

 the abdomen. 



Geographical distribution. — As a species Chordeiles virginianus 

 ranges, during the breeding season, in the West Indies and North 

 America, form the northern edge of Mexico, the Gulf coast of the 

 United States, and the Greater Antilles, north, to the edge of the 

 Barren Grounds in central Quebec, northern Ontario, southern 

 Mackenzie, and northern Yukon ; and from the Atlantic coast to the 

 Pacific. It migrates across Mexico, Central America, and through 

 the West Indies to southern South America, where the various sub- 

 species probably winter together. 



The summer ranges of two of the races, Chordeiles virginianus 

 aserriensis'^ and Chordeiles virginianus vicinus, is somewhat re- 

 stricted geographically, but most of the others are considerably ex- 

 tended. The northernmost form, Chordeiles virginianus virginianus, 

 occupies an immense area stretching all the way across the continent, 

 and at least equal in extent to the combined ranges of all the other 

 subspecies. 



The breeding areas of all but two of the forms of Chordeiles vir- 

 ginianus are continuous with some one or more of the others, al- 

 though, of course, the lines delimiting the ranges on the accompany- 

 ing map leave intermediate spaces due to lack of specimens from such 

 regions. The subspecies of the Greater Antilles, Chordeiles vir- 

 ginianus TThintOr, and that of the Bahama Islands, Chordeiles vir- 

 ginianus vicinus, are, of course, separated from each other and from 

 the mainland forms by the surrounding water. The southeastern 

 bird, Chordeiles virginianus chapmani, adjoins Chordeiles virginianus 

 virginianus, Chordeiles virginianus howelli,^ and Chordeiles vir- 

 ginianus aserriensis} Also Chordeiles virginianus virginianus west- 

 ward meets Chordeiles virginianus howelli^ Chordeiles virginianus 

 sennetti and Chordeiles virginianus hesperis; and the last also reaches 

 Chordeiles virginianus sennetti. The central form of the west, Chor- 

 deiles virginianus howelli,^ lies surrounded by all of the six other 

 mainland races, every one of which it touches at some part of the 

 boundary of its range, as the distribution map shows. The far south- 

 western bird, Chordeiles virginianus henry i, adjoins, in addition, 

 Chordeiles virginianus aserriensis on the southeast, and probably also 

 Chordeiles virginianus hesperis on the northwest. 



Zonal distribution. — In the West Indies during summer this species 

 occupies the Upper Tropical Zone of the Neotropical Region; on 

 the North x^merican Continent the Lower Austral, Upper Austral, 



1 See p. 71. 



2 See p. 57. 



