NIGHTJAR 



641 



not here be mentioned, the genns A''i/ctidromus, though consisting of only- 

 one species (iV. alhicollis) which, though varying somewhat in size and 

 coloration, ranges from Texas to Southern Brazil, requires remark, 

 since it has tarsi of sufficient length to enable it to run swiftly on the 

 ground, while the legs of most birds of the Family are so short that 

 they can make but a shi;ffling progress. The South-American 

 Heleothreptes, with the peculiar form of wing (counting from the 

 wrist, in Avhich the 2nd, 3rd, and 4th primaries are greatly elongated) 

 possessed by the male, needs mention ; but a still more exaggerated 

 condition exists in two African species, referred by some ornithologists 



Pennant-winged Nightjar, Macrodipteryx. 

 (After sketch from life by J. Gedge.) 



to as many genera {Macrodipteryx and Cosmetornis) though probably 

 one genus would suffice for both. The males of each of them are 

 characterized by the wonderful development of the 2nd primary, 

 which reaches in adult specimens the extraordinary length of 17 

 inches or more. The former of these, the Ccqmmulgus macrodipterus 

 of Afzelius, seems to have the more northern range, occurring across 

 the continent from Abyssinia to the West Coast, and the shaft of 

 the elongated remiges is bare for the greater part of its length, 

 retaining the web, in a spatulate form, only near the tip. The 

 latter, to Avhich the specific name of vexillarius was given by Mr. 

 Gould, inhabits equatorial Africa, and thence to Damaraland on 



41 



