188 BRITISH BIRDS. 



Genus PKOGNE. 



The genus Progne was established in 1826 by Boie, in the ' Isis ' for 

 that year (p. 971), for the reception of the Purple Martin, which thus 

 became the type. The birds in this genus may be distinguished by having 

 the nostrils opening upwards and exposed, without any internal overhanging 

 membrane. Some of the species have a metallic gloss on the feathers of 

 the upper parts, whilst others are uniform brown. It is impossible to 

 state how many species there are in this genus, many Swallows pre- 

 senting characters intermediate between it and Hirundo. On the widest 

 estimate the number of species would be between thirty and forty, which 

 are confined to the Nearctic, Neotropical, and Ethiopian Regions. The 

 narrowest estimate would reduce the number of species to four, belonging 

 to the Nearctic and Neotropical Regions only. The sole representative of 

 this genus in Europe is the Purple Martin, which is supposed on more than 

 one occasion to have accidentally strayed as far as the British Islands. 



It is not known that the species of this genus differ from those of 

 Hirundo in habits, food, or nidification. 



