224 FIELD MUSEUM OF NATURAL HISTORY ZOOLOGY, VOL. IX. 



GROUP 2. Wing, 4.75 to 5.50 inches long. 



Male: General plumage (including belly), bluish black, or dark 

 steel blue. 



Female: Back, like male; under parts, grayish brown, shading 

 into dull white on the belly. Immature birds have the upper plumage, 

 brownish; under parts, brownish on the breast; dull white on the 

 belly. Progne subis. 



Purple Martin. 

 See No. 282. 



Back, steel blue; belly, white. Iridoprocne bicolor. 



Tree Swallow. White-bellied Swallow. 



See No. 285. 



Back, steel blue; under parts, cinnamon brown; tail, very deeply 

 forked. Hirundo eryihrogastra. 



Barn Swallow. 



See No. 284. 



