114 THE CHICAGO ACADEMY OF SCIENCES. 



and adds: "The spring of 1876, I found these birds breeding, 

 with var. popetue in considerable numbers among the sand hills 

 on the Lake shore, near Waukegan. I should judge that the two 

 forms existed in about equal numbers at that place. They are, 

 however, less common in other localities I have visited. Among 

 the specimens examined were individuals that exhibited a perfect 

 intergradation of the two forms. Some specimens would have 

 the white patch on the wings like those in typical henryi, while 

 the tail was marked as in popetue, and vice versa. Other speci- 

 mens showed a varying degree of white, on the wings and tail, 

 between the two varieties. In none is the lightness of the back 

 quite so prominent as in specimens from the western plains." 



The range of the Nighthawk includes eastern North America, 

 west to the Great Plains and central British Columbia, and from 

 Labrador south through tropical America to the Argentine Re- 

 public. 



FAMILY MICROPODID^E: SWIFTS. 

 Genus CENTURA Stephens, 1825. 



Chaetura pelagica (LinnaBus). Chimney Swift. 



Hirundo pelagica LINNAEUS, S. N., ed. 10, I, 1758, 192. 

 Cypselus pelasgius BONAPARTE, Syn. 1828, 63. 

 ChcBtura pelasgia STEPH., Gen. Zool., XIll, pt. ii, 1825, 76. 

 Popular synonyms: CHIMNEY SWALLOW. CHIMNEY SWEEP. 



A common summer resident, arriving late in April and depart- 

 ing about the middle of September. 



Its range covers eastern North America east of the Plains, and 

 from Labrador and the Fur Countries southward. It winters 

 south of the United States so far as known. 



FAMILY TROCHILIIXaE: HUMMINGBIRDS. 

 Genus TROCHILUS Linnaeus, 1758, 



Trochilus colubris Linnaeus. Ruby-throated Hummingbird. 

 Trochilus colulris LINNAEUS, S. N., ed. 10, I, 1758, 120. 



A common summer resident, arriving the last of April and 

 departing in September. Mr. A. W. Carter found two nests of 

 this species in May, 1905. One of these, which he found near 

 Wolf Lake, Indiana, about the first of the month, contained fresh 

 eggs. The other, which he saw about May 10, contained young 



